—n. 1. a subordinate or supplementary part, object, or the like, used mainly for convenience, attractiveness, safety, etc., as a spotlight on an automobile or a lens cover on a camera.
2. an article or set of articles of dress, as gloves, earrings, or a scarf, that adds completeness, convenience, attractiveness, etc., to one's basic outfit.
3. Law. a. Also calledacces'sory before' the fact'. a person who, though not present during the commission of a felony, is guilty of having aided and abetted another, who committed the felony.
b. Also calledacces'sory af'ter the fact'. a person who knowingly conceals or assists another who has committed a felony. Cf. principal (def. 9b).
4. Anat.See accessory nerve.
—adj. 1. contributing to a general effect; supplementary; subsidiary.
2. Law.giving aid as an accessory.
3. Petrog.noting any mineral whose presence in a rock has no bearing on the classification of the rock, as zircon in granite.