quantum

Etymology

From Late Latin quantum, noun use of neuter form of Latin quantus (“how much”).

noun

1. (now chiefly South Asia or law) The total amount of something; quantity.
   1. (law) The amount of compensation awarded to a successful party in a lawsuit.
   2. (law) The length or magnitude of the sentence handed down to someone who has been found guilty of a crime.
2. The amount or quantity observably present, or available.
   Each man has only a quantum of compassion, he argued, and mine is used up for the day. 1979, John Le Carré, Smiley's People, Folio Society, published 2010, page 96
   The dream of flying, according to Strümpell, is the appropriate image used by the psyche to interpret the quantum of stimulus [translating Reizquantum] proceeding from the rise and fall of the lungs when the cutaneous sensation of the thorax has simultaneously sunk into unconsciousness. 1999, Sigmund Freud, translated by Joyce Crick, The Interpretation of Dreams, Oxford, published 2008, page 34
3. (physics) The smallest possible, and therefore indivisible, unit of a given quantity or quantifiable phenomenon.
   The quantum of light energy was later called a photon. 2002, David C Cassidy et al., Understanding Physics, Birkhauser 2002, p. 602
4. (computing) The amount of time allocated for a thread to perform its work in a multithreaded environment.
5. (computing, uncountable) Short for quantum computing.
   Developing for quantum has never been more accessible.
6. (medicine) The minimum dose of a pathogen required to cause an infection.
7. (mathematics) A definite portion of a manifoldness, limited by a mark or by a boundary.
   Defined parts of a manifoldness are called Quanta 1882, William Kingdon Clifford, Mathematical Papers

adj

1. Of a change, sudden or discrete, without intermediate stages.
2. (informal) Of a change, significant.
3. (physics) Involving quanta, quantum mechanics or other aspects of quantum physics.
   Some of the most beautiful and thus appealing physical theories, including quantum electrodynamics and quantum gravity, have been dogged for decades by infinities that erupt when theorists try to prod their calculations into new domains. Getting rid of these nagging infinities has probably occupied far more effort than was spent in originating the theories. 2012-01, Michael Riordan, “Tackling Infinity”, in American Scientist, volume 100, number 1, archived from the original on 2017-06-19, page 86
   1. (computing theory) Relating to a quantum computer.