(linguistics) One of two or more differentwords in a language derived from the same etymological root but having different phonological forms (e.g., toucher and toquer in French or pyre and fire in English).
(literature) In textual criticism, two different narrativeaccounts of the same actual event.
(lapidary) An imitationgem made of two pieces of glass or crystal with a layer of color between them.
(printing, US) A word or phrase set a second time by mistake.
(quantum mechanics) A quantum state of a system with a spin of ½, such that there are two allowed values of the spin component, −½ and +½.