Source : WordNet®

quark
     n 1: 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
     2: fresh unripened cheese of a smooth texture made from
        pasteurized milk, a starter, and rennet [syn: {quark
        cheese}]