A fundamental particle believed to be the primary constituent of all mesons and baryons; quarks have a charge that is a fraction of 1 electron charge and interact through electromagnetic and nuclear forces. Six varieties are thought to exist with the unusual names of up, down, strange, charmed, bottom, and top.
[a word of indeterminate sense used by James Joyce in his novel Finnegans Wake]
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Examples: glitazone, GI cocktail, etc.