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Glossary · Q
49 terms defined in plain English, each with a link to articles that use it.
The Qadiri is a Sufi order named after Abdul Qadir Gilani of Baghdad (died 1166) that combined mystic devotion with strict adherence to orthodox Sunni law, the sharia. It reached India in the Sultanate period and gained court influence under the Mughals, notably through Prince Dara Shikoh, who was initiated into the order and wrote on mysticism. For UPSC it illustrates the diversity of Sufi silsilas beyond the Chishti and Suhrawardi orders.
Example: Dara Shikoh
A qanungo was a hereditary revenue record-keeper in the Mughal and later British land administrations. He maintained village-level records of land ownership, assessments, and collections, acting as the registrar between the cultivator and the state. The office reveals how pre-colonial fiscal institutions were absorbed by colonial rule. It serves GS-1 medieval Indian administration and GS-2 land reforms.
Example: the qanungos of Akbar's revenue system, which recorded the dahsala settlements
Qarachil is the Himalayan frontier region, identified with the Kumaon-Garhwal hills, against which Sultan Muhammad bin Tughlaq launched a military expedition in the 1330s. His large army was destroyed by harsh terrain, cold and local resistance, with chroniclers reporting almost total losses. The disaster is cited alongside the capital transfer and token currency as evidence of Tughlaq's overambitious, ill-planned projects in UPSC medieval history.
Example: Muhammad bin Tughlaq's Qarachil expedition, c. 1330s
Qartemi is the brand name of varnimcabtagene autoleucel (IMN-003A), a CAR T-cell therapy developed by the Bengaluru-based Immuneel Therapeutics. Approved by the Central Drugs Standard Control Organisation in January 2025, it is India's second approved CAR T-cell therapy after NexCAR19, indicated for adult patients with relapsed or refractory B-cell Non-Hodgkin Lymphoma. It is a personalized living drug made by genetically engineering the patient's own T cells to attack cancer cells, and is priced at roughly one-tenth of comparable products in the United States.
Example: Its launch in January 2025 as a treatment option for Indian adults with relapsed B-cell Non-Hodgkin Lymphoma
Qawwali is a form of Sufi devotional music performed in groups, with powerful lead vocals, rhythmic clapping and harmonium and tabla accompaniment, expressing spiritual love and longing for the divine. Associated with the Chishti order and credited in origin to Amir Khusrau, it is sung at dargahs and in concert settings. For UPSC it belongs to medieval cultural history and composite culture.
Example: Evening qawwali sessions at the Nizamuddin Dargah in Delhi draw devotees and visitors alike.
The Qazi of Delhi is the office of chief judge of the Delhi Sultanate, charged with administering Islamic law in the capital. Its most famous holder was the historian Minhaj-us-Siraj, appointed chief qazi under Iltutmish and continued under his successors, who later authored the Tabaqat-i-Nasiri, the principal Persian source for the early Sultanate. It matters for UPSC as an example of the judiciary's place in Sultanate administration.
Example: Minhaj-us-Siraj
The qazi-ul-quzzat was the chief qazi, or head of the judiciary, under the Delhi Sultanate. He oversaw the network of qazis who applied Islamic law in disputes, and he stood among the highest officials of the Sultan's court. The office shows the Sultanate's fusion of religious law with state administration. It serves GS-1 medieval Indian polity.
A qiladar was the commander of a fort in Mughal and Maratha administration. Responsible for the fort's garrison, stores, and defence, he was a key military officer whose loyalty secured the ruler's hold over strategic strongholds. Forts were the pivots of territorial control in pre-colonial India. The term serves GS-1 medieval military administration.
Qisse are narrative poems and tales in Punjabi, Sindhi and Urdu literature, from the Arabic word qissa meaning a story, which flourished from the sixteenth century as sung romances blending love, Sufi allegory and folk motifs. Recited at gatherings, they celebrate loyalty, promise (qaul) and defiance of oppressive custom. The most famous is Waris Shah's Heer Ranjha of 1766, a staple of UPSC questions on regional literature.
Example: Waris Shah's Heer Ranjha (1766)
QKD is the abbreviation for Quantum Key Distribution, a quantum communication technique for sharing encryption keys with security guaranteed by the laws of physics. Any attempt to eavesdrop on the key exchange disturbs the quantum states being transmitted and reveals the intrusion. See the full entry under Quantum Key Distribution (QKD).
Example: A bank using a QKD link to distribute encryption keys between two data centers with eavesdropping-proof security
QpiAI-Indus is India's first full stack quantum computer, a 25 qubit superconducting system developed by the Bengaluru startup QpiAI and unveiled on World Quantum Day, 14 April 2025. It was developed with support from the National Quantum Mission (coordinated by the Department of Science and Technology) and integrates indigenous quantum hardware, control systems and software.
Example: QpiAI followed it with Kaveri, a 64 qubit system, launched in November 2025.
QSim, the Quantum Computer Simulator Toolkit, is India's first indigenously developed quantum computing toolkit, launched by the Ministry of Electronics and Information Technology in 2021. Developed jointly by IISc Bengaluru, IIT Roorkee, and C-DAC, it lets researchers and students write, debug, and test quantum algorithms on classical computers in a cost-effective way, including simulating noisy quantum circuits to prepare for real hardware. It serves as an educational and research platform for building quantum programming skills.
Example: A student testing and debugging Grover's search algorithm in QSim's graphical workbench before running it on an actual quantum processor
Quad is the strategic dialogue of India, the United States, Japan and Australia, aimed at a free and open Indo-Pacific. It is not a formal military alliance but a flexible platform for cooperation on maritime security, critical technologies, supply chains and humanitarian assistance. For UPSC, it exemplifies India's multi-alignment: deepening US partnership while preserving strategic autonomy and engaging China-adjacent security concerns without a treaty commitment.
Example: The first Quad Leaders' Summit, held virtually in March 2021, which launched working groups on vaccines, climate and critical tech.
Qualitative, in the UPSC economics context, describes the RBI's selective instruments of credit control, which target the use and direction of credit rather than its total volume. These include margin requirements, moral suasion, credit rationing and selective credit controls. For UPSC the qualitative versus quantitative distinction is a standard monetary policy question.
Example: The RBI's margin requirements on advances against shares restrain speculative lending without changing overall money supply.
Quality of life is the overall well-being of individuals and societies, measured through health, education, income, environment, and freedom rather than through income alone. It underpins human development thinking and the sustainable development goals, and it is the standard against which welfare schemes are judged. It serves GS-2 social justice and GS-3 inclusive growth.
Example: the UNDP's Human Development Index, first published in 1990
Quantifiable data is information expressed in numbers that can be counted, measured, and statistically analysed, such as literacy rates, crop yields, or fiscal deficits. It is the backbone of evidence-based policymaking, programme evaluation, and census or survey design. It serves GS-2 governance and GS-3 economic data analysis.
Quantitative describes the RBI's general instruments of credit control, which change the total volume of money and credit in the economy, chiefly the repo rate, Cash Reserve Ratio, Statutory Liquidity Ratio and open market operations. For UPSC these are the standard tools tested under monetary policy and inflation control.
Example: The RBI's March 2020 cut of the Cash Reserve Ratio by 100 basis points to 3 percent released about Rs 1.37 lakh crore of primary liquidity during the pandemic.
In physics, a quantum (plural: quanta) is the smallest discrete unit of a physical property, such as a photon being the quantum of light. The quantum hypothesis, introduced by Max Planck in 1900 to explain black-body radiation, holds that energy is absorbed and emitted in indivisible packets rather than continuously. It is the founding idea of quantum mechanics and of the technologies grouped under quantum today.
Example: A photon, the quantum of electromagnetic energy, underlies both solar cells and quantum communication systems.
Quantum communication is the use of quantum phenomena such as superposition and entanglement to transmit information with security or capabilities beyond classical communication. Its flagship application is Quantum Key Distribution, which makes eavesdropping detectable, and longer-term goals include quantum networks and a quantum internet linking quantum computers. It is one of the four verticals of India's National Quantum Mission, alongside computing, sensing, and materials.
Example: Two institutions exchanging encryption keys over a QKD-secured optical fiber link, where any interception attempt would be detected
Quantum computing is a computing paradigm that uses quantum bits (qubits), which exploit superposition and entanglement to process information in ways classical bits cannot. Certain problems, such as factoring large numbers or simulating molecules, could in principle be solved far faster than on classical machines. Practical machines remain noisy and small, and India's National Quantum Mission (approved in 2023) has quantum computing as a core focus.
Example: Google's 2019 Sycamore processor performing a specific sampling task in 200 seconds, a task it claimed would take a leading supercomputer thousands of years.
Quantum cryptography, also called quantum encryption or Quantum Key Distribution, refers to various cybersecurity methods for encrypting and transmitting secure data based on the naturally occurring and immutable laws of quantum mechanics.
The Quantum Diamond Microscope is India's first indigenous instrument for dynamic magnetic-field imaging, developed by the P-Quest Group at IIT Bombay under the National Quantum Mission and announced in November 2025. It is based on nitrogen-vacancy centers in diamond, atomic-scale defects that retain quantum coherence at room temperature and are extremely sensitive to magnetic variations, read out optically through a technique called optically detected magnetic resonance. It enables three-dimensional magnetic-field imaging at the nanoscale, with applications in neuroscience, materials research, and non-destructive evaluation of semiconductor chips.
Example: Mapping buried current paths inside an encapsulated semiconductor chip in 3D without destroying it
Quantum dots are nanoscale semiconductor crystals, typically a few nanometers across, whose optical and electronic properties change with their size because of quantum confinement effects. They emit bright, pure colors when illuminated or electrified, making them valuable in displays, medical imaging, and solar cells. Their discovery and synthesis was recognized with the 2023 Nobel Prize in Chemistry.
Example: QLED television displays, which use quantum dots to produce brighter and more vivid colors
Quantum effects are phenomena that appear when matter is confined to nanometre scales, where classical physics breaks down and quantum mechanics takes over. Examples include quantum confinement, where shrinking a semiconductor changes its colour and conductivity, and tunnelling, where particles pass through barriers they classically could not cross. Nanotechnology deliberately engineers these effects for new materials and devices.
Example: Quantum dots glowing in different colours depending on their size, used in QLED television displays.
Quantum Key Distribution is a method of secure communication that uses quantum-mechanical properties of particles, typically photons, to share encryption keys between two parties. Because measuring a quantum system disturbs it, any eavesdropping attempt on the key exchange is immediately detectable, giving QKD security rooted in physics rather than computational difficulty. It is a leading application of quantum communication and a focus area of India's National Quantum Mission.
Example: A bank using a QKD link to distribute encryption keys between two data centers with eavesdropping-proof security
Quantum Key Distribution (QKD) is a method of secure communication that uses quantum-mechanical properties of particles, typically photons, to share encryption keys between two parties. Because measuring a quantum system disturbs it, any eavesdropping attempt on the key exchange is immediately detectable, giving QKD security rooted in physics rather than computational difficulty. It is a leading application of quantum communication and a focus area of India's National Quantum Mission.
Example: A bank using a QKD link to distribute encryption keys between two data centers with eavesdropping-proof security
Quantum materials and devices is a research theme covering materials that exhibit pronounced quantum phenomena, such as superconductors and topological materials, and the devices built from them, including quantum sensors, magnetometers, and single-photon sources. Advances here underpin practical quantum technologies in sensing, metrology, and communication. It is one of the focus areas of India's National Quantum Mission.
Example: The indigenous Quantum Diamond Microscope developed at IIT Bombay, a quantum sensing device for nanoscale magnetic-field imaging
Quantum mechanics is the branch of physics describing nature at the atomic and subatomic scale, where energy, momentum and other quantities come in discrete packets. Its core principles include superposition, the uncertainty principle and entanglement. Developed in the 1920s by figures such as Heisenberg, Schrodinger and Dirac, it underpins semiconductors, lasers and all quantum technologies.
Example: The transistors in every smartphone work because quantum mechanics explains how electrons behave inside semiconductors.
Quantum sensing and metrology is the use of quantum phenomena such as superposition and entanglement to measure physical quantities with far greater precision than classical instruments allow. It is one of the four verticals of India's National Quantum Mission, alongside quantum computing, quantum communication, and quantum materials. Practical uses include atomic clocks that keep time to within a fraction of a second over millions of years, and gravimeters that detect underground mineral deposits or groundwater.
Example: Atomic clocks used in navigation satellites rely on quantum transitions of atoms to maintain ultra-precise time.
Quantum technology is any technology that exploits the rules of quantum mechanics, such as superposition, entanglement and tunnelling, to perform tasks impossible for classical devices. Its main branches are quantum computing, quantum communication, quantum sensing and metrology, and quantum materials and devices. India approved the National Quantum Mission in 2023, with a budget of Rs 6,003.65 crore for 2023-24 to 2030-31, to build capability in all four areas.
Example: Quantum key distribution uses entangled photons to create encryption keys that reveal any eavesdropping, making interception detectable.
A qubit is the basic unit of quantum information, the quantum analogue of the classical bit. While a bit is either 0 or 1, a qubit can exist in a superposition of both states until measured, and multiple qubits can be entangled so their states are correlated. Physical realisations include superconducting circuits, trapped ions and photons.
Example: The superconducting qubits used by IBM and Google, cooled to near absolute zero, form the processors in today's experimental quantum computers.
Queen Naganika is the Satavahana queen, wife of King Satakarni I (circa 70-60 BCE), who issued the Nanaghat inscription in the Western Ghats of Maharashtra. The Brahmi inscription records the Vedic sacrifices performed by her house, including the ashvamedha and rajasuya, and lists early Satavahana rulers. It is one of the earliest epigraphic sources for Deccan history and a recurring UPSC prelims question on inscriptions.
Example: Nanaghat inscription
Queen Victoria's Proclamation of 1 November 1858 is the royal declaration that transferred the government of India from the East India Company to the British Crown after the Revolt of 1857. Read at Allahabad by Lord Canning, it promised no further annexations, respect for Indian religions and customs, and admission of Indians to offices by qualification. For UPSC it marks the constitutional beginning of the British Raj and the end of Company rule.
Example: Read by Lord Canning at Allahabad, 1 November 1858
Queen Victoria's Proclamation of 1 November 1858 is the royal declaration that transferred the government of India from the East India Company to the British Crown after the Revolt of 1857. Read at Allahabad by Lord Canning, it promised no further annexations, respect for Indian religions and customs, and admission of Indians to offices by qualification. For UPSC it marks the constitutional beginning of the British Raj and the end of Company rule.
Example: Read by Lord Canning at Allahabad, 1 November 1858
The Queen's Proclamation is the royal declaration of 1 November 1858 by which Queen Victoria assumed direct rule of India, ending the East India Company's government after the 1857 Revolt. Proclaimed at Allahabad by Lord Canning, it pledged non-interference in religion, no further territorial annexation, and equal treatment of Indians in public service. It is a landmark UPSC topic for the transition from Company rule to Crown rule.
Example: Read by Lord Canning at Allahabad, 1 November 1858
The Queen's Proclamation read at Allahabad in November 1858 is the public announcement by Lord Canning of Queen Victoria's assumption of India's government, issued on 1 November 1858 after the Revolt of 1857. The reading ceremony at Allahabad formally ended East India Company rule, promised religious neutrality and no further annexations, and opened Crown service to qualified Indians. For UPSC it is the standard date-and-place fact for the birth of the British Raj.
Example: Lord Canning's durbar at Allahabad, 1 November 1858
QuEST (Quantum Enabled Science and Technology) is the DST programme supporting quantum capability building across institutions, complementing the National Quantum Mission.
Quid pro quo is a Latin phrase meaning something given in exchange for something else, denoting a reciprocal bargain of favours or benefits. In UPSC contexts it appears in ethics and governance answers to describe corrupt exchanges, conflicts of interest and patronage, and in international relations to describe reciprocal concessions between states. It carries no single fixed example, so none is given.
Quit India is the slogan and resolution adopted by the Congress at Bombay on 8 August 1942, launching the final mass movement against British rule under Gandhi's call of Do or Die. The immediate arrest of the entire Congress leadership triggered a spontaneous, leaderless uprising of strikes, sabotage and parallel governments across India. It is central to UPSC modern history as the last great nationalist upsurge before independence.
Example: Launched 8 August 1942 at Gowalia Tank Maidan, Mumbai
The Quit India Movement is the mass upsurge launched by the Congress at Bombay on 8 August 1942 with Gandhi's call of Do or Die, demanding immediate British withdrawal from India. With the leadership jailed the same night, the revolt turned spontaneous, featuring strikes, underground networks led by figures like Jayaprakash Narayan and parallel governments at Ballia and Satara. For UPSC it is the climactic movement of the freedom struggle.
Example: Launched 8 August 1942 at Gowalia Tank Maidan, Mumbai
The Quit Kashmir movement of 1946 is the agitation launched in May 1946 by Sheikh Abdullah's National Conference demanding that Maharaja Hari Singh devolve power to the people's representatives in the princely state of Jammu and Kashmir. Abdullah was arrested and jailed for sedition, while Jawaharlal Nehru's attempt to enter the state to defend him led to his own detention at the border. It is key for UPSC on princely-state politics before accession.
Example: Sheikh Abdullah's arrest, May 1946
Quo warranto is a prerogative writ, meaning by what authority, through which a court asks a person holding a public office to show the legal right on which they hold it. It is issued against the unlawful occupation of a substantive public office and protects the public from usurpers. For UPSC polity it is one of the five writs under Articles 32 and 226, tested alongside habeas corpus and mandamus. It carries no single fixed example, so none is given.
Qure.ai is a Mumbai-based health-technology company that uses artificial intelligence to interpret medical scans. Its deep-learning software reads chest X-rays to detect tuberculosis, pneumonia and other lung conditions with high accuracy. It is an example of AI being deployed for affordable healthcare in settings where trained radiologists are scarce.
Example: Qure.ai's chest X-ray software screens patients for tuberculosis, supporting TB detection drives in India.
Qutb Minar is the 73-metre red sandstone minaret in Delhi begun by Qutb-ud-din Aibak and completed by Iltutmish in the early thirteenth century. Its five tapering storeys, carved inscriptions and projecting balconies make it the supreme early monument of Indo-Islamic architecture in India and a UNESCO World Heritage Site. It is a standard UPSC prelims fact for the Mamluk dynasty and Sultanate art.
Example: UNESCO World Heritage inscription, 1993
The Qutb Minar complex is the archaeological ensemble in Delhi centred on the Qutb Minar, containing the Quwwat-ul-Islam mosque, the Alai Darwaza, the Alai Minar and the famous rust-resistant iron pillar. Built over the thirteenth and fourteenth centuries by successive Sultans, it displays the evolution of early Indo-Islamic architecture and is a UNESCO World Heritage Site. It is a core UPSC topic for Sultanate monuments.
Example: Iron pillar of Chandragupta II
The Qutb Shahi is the dynasty founded by Sultan Quli Qutb-ul-Mulk that ruled the Golconda Sultanate in the Deccan from 1518 to 1687. Its rulers built the fort city of Golconda, founded Hyderabad in 1591 under Muhammad Quli Qutb Shah, raised the Charminar, and patronised Deccani Urdu and Telugu culture before Aurangzeb's annexation. For UPSC it represents the Deccan sultanates between Vijayanagara and the Mughals.
Example: Charminar, Hyderabad (1591)
Qutb-ud-din Aibak is the former slave general of Muhammad Ghori who became the first Sultan of Delhi in 1206, founding the Mamluk or Slave dynasty. He commissioned the Qutb Minar and the Quwwat-ul-Islam mosque in Delhi and ruled briefly until his death in a polo accident at Lahore in 1210. For UPSC he is the starting point of the Delhi Sultanate's chronology and Sultanate architecture.
Example: Death in a polo accident at Lahore, 1210
Qutbuddin Bakhtiyar Kaki is the Chishti Sufi saint, disciple of Khwaja Moinuddin Chishti, who settled in Delhi during Iltutmish's reign and died in 1235. Iltutmish held him in deep reverence, and the Qutb Minar is traditionally named after him rather than after Qutb-ud-din Aibak. His dargah at Mehrauli remains a major shrine. He matters for UPSC on Sufi orders and their ties with Sultanate rulers.
Example: Dargah at Mehrauli, Delhi
The Quwwat-ul-Islam mosque is the first congregational mosque built in Delhi, commissioned by Qutb-ud-din Aibak in 1192 within the Qutb complex. Raised on the site of earlier structures with richly carved pillars, it marks the beginning of Indo-Islamic architecture in India, blending Islamic arches and screens with indigenous stonework. It is a foundational UPSC monument for the Slave dynasty's building programme.
Example: Commissioned 1192