ac·ces·so·ry 
(ăk-sĕsə-rē)
(ăk-sĕsə-rē)n. pl. ac·ces·so·ries
1.
a. A subordinate or supplementary item; an adjunct.
b. Something nonessential but desirable that contributes to an effect or result. See Synonyms at attachment.
2. Law One who knowingly assists a lawbreaker in the commission of a crime but does not actually participate in that crime.
adj.
1. Having a secondary, supplementary, or subordinate function.
2. Law Involving the knowing assistance of a lawbreaker in the commission of a crime without actual participation in the crime.
[Middle English accessorie, from Medieval Latin accessōrius, from accessor, helper, from Latin accessus, approach; see ACCESS.]
ac′ces·sori·al (-sə-sôrē-əl) adj.
ac·cesso·ri·ly adv.
Usage Note: Although the pronunciation (ə-sĕsə-rē), with no (k) sound in the first syllable, is sometimes heard, it is not accepted by a majority of the Usage Panel. In the 1997 survey, 87 percent of the Panelists disapproved of it. The 2012 survey showed an 80 percent disapproval rate.