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.

Also called accessory 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.

Also called accessory after the fact. a person who knowingly conceals or assists another who has committed a felony.

Compare principal (def 9b).

4. Anatomy. accessory nerve.