What is Accessory?

Legal Definition
An accessory is a person who assists in the commission of a crime, but who does not actually participate in the commission of the crime as a joint principal. The distinction between an accessory and a principal is a question of fact and degree:

  • The principal is the one whose acts or omissions, accompanied by the relevant mens rea (Latin for "guilty mind"), are the most immediate cause of the actus reus (Latin for "guilty act").
  • If two or more people are directly responsible for the actus reus, they can be charged as joint principals (see common purpose). The test to distinguish a joint principal from an accessory is whether the defendant independently contributed to causing the actus reus rather than merely giving generalised and/or limited help and encouragement.
-- Wikipedia
Legal Definition
Someone aiding in or contributing to the commission or concealment of a felony, e.g. by assisting in planning or encouraging another to commit a crime (an accessory before the fact) or by helping another escape arrest or punishment (an accessory after the fact). An accessory, unlike an accomplice, is typically not present when the crime is committed.
Illustrative caselaw
See, e.g. Lankford v. Idaho, 500 U.S. 110 (1990).
See also
Legal Definition
Property. Everything which is joined to another thing, as an ornament, or to render it more perfect, is an accessory, and belongs to the principal thing. For example, the halter of a horse, the frame of a picture, the keys of a house, and the like; but a bequest of a house would not carry the furniture in it, as accessory to it. Domat, Lois Civ. Part. 2, liv. 4, tit. 2, s. 4, n. 1. Accesiorium non ducit, sed sequitur principale. Co. Litt. 152, a. Co. Litt. 121, b. note (6). Vide Accession; Adjunction; Appendant; Appurtenances; Appurtenant; Incident.
-- Bouviers Law Dictionary
Legal Definition
Anything which is joined to another thing as an ornament or to render it more perfect or which accompanies it or is connected with it as an incident or as subordinate to it or which belongs to or with it. In criminal law. An accessary. The latter spelling is preferred. See that title.
-- Black's Law Dictionary
Legal Definition
One who aids or abets the commission of a crime and is absent at the time. See 5 Am St. Rep. 512.
-- Ballentine's Law Dictionary