QUARK
quark
(noun) (physics) hypothetical truly fundamental particle in mesons and baryons; there are supposed to be six flavors of quarks (and their antiquarks), which come in pairs; each has an electric charge of +2/3 or -1/3; “quarks have not been observed directly but theoretical predictions based on their existence have been confirmed experimentally”
Source: WordNet® 3.1
Etymology 1
Noun
quark (plural quarks)
(particle) In the Standard Model, an elementary subatomic particle that forms matter. They combine to form hadrons, such as protons and neutrons.
(computing, X Window System) An integer that uniquely identifies a text string.
Hyponyms
• beauty quark
• bottom quark
• charm quark
• down quark
• strange quark
• top quark
• truth quark
• up quark
Etymology 2
Noun
quark (uncountable)
A soft creamy cheese, eaten throughout northern, central, and eastern Europe, very similar to cottage cheese except that it is usually not made with rennet.
Etymology 3
Noun
quark (plural quarks)
(Falkland Islands, informal) The black-crowned night heron, Nycticorax nycticorax.
Source: Wiktionary