accessory

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A subordinate or supplementary item; an adjunct.
• noun Something nonessential but desirable that contributes to an effect or result. synonym: attachment.
• noun Law One who knowingly assists a lawbreaker in the commission of a crime but does not actually participate in that crime.
• adjective Having a secondary, supplementary, or subordinate function.
• adjective Law Involving the knowing assistance of a lawbreaker in the commission of a crime without actual participation in the crime.

from The Century Dictionary.

• (Of persons.) Acceding; contributing; aiding in producing some effect, or acting in subordination to the principal agent: usually in a bad sense: as, accessory to a felony. Technically, in law, it implies aiding without being present at the act.
• (Of things.) Contributing to a general effect; aiding in certain acts or effects in a secondary manner; belonging to something else as principal; accompanying: as, accessory sounds in music; accessory muscles. Additional, or of the nature of an appendage: as, accessory buds are developed by the side of or above the normal axillary bud.
• noun In law, one who is guilty of a felony, not by committing the offense in person or as a principal, nor by being present at its commission, but by being in some other way concerned therein, as by advising or inciting another to commit the crime, or by concealing the offender or in any way helping him to escape punishment.
• noun That which accedes or belongs to something else as its principal; a subordinate part or object; an accompaniment.
• noun In the fine arts, an object represented which is not a main motive or center of interest, but is introduced to balance the composition or in some way enhance its artistic effectiveness.
• noun Synonyms Abetter, accomplice. See the definitions of these words.
• In the logical system of Lotze, adding (as thought) to the coherence of the matter of thought a notion of the ground of its coherence. See the extract.
• In geology, noting those minerals which are present in relatively small quantities in a rock and are not mentioned in its definition, such as zircon, apatite, and magnetite in granite: contrasted with essential.
• noun In organ-building, same as accessory stop.

from the GNU version of the Collaborative International Dictionary of English.

• noun That which belongs to something else deemed the principal; something additional and subordinate.
• noun (Law) Same as Accessary, n.
• noun (Fine Arts) Anything that enters into a work of art without being indispensably necessary, as mere ornamental parts.
• adjective Accompanying as a subordinate; aiding in a secondary way; additional; connected as an incident or subordinate to a principal; contributing or contributory; said of persons and things, and, when of persons, usually in a bad sense

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• adjective Having a secondary, supplementary or subordinate function by accompanying as a subordinate; aiding in a secondary way; being additional; being connected as an incident or subordinate to a principal; contributing or being contributory. Said of persons and things, and, when of persons, usually in a bad sense; as, he was accessory to the riot; accessory sounds in music.
• adjective law Assisting a crime without actually participating in committing the crime itself.
• adjective Present in a minor amount, and not essential.
• noun That which belongs to something else deemed the principal; something additional and subordinate, an attachment.
• noun fashion An article that completes one's basic outfit, such as a scarf or gloves.
• noun law One who, not being present, contributes as an assistant or instigator to the commission of an offense; One who assists after the commission of a crime, but was not present.
• noun art Anything that enters into a work of art without being indispensably necessary, as mere ornamental parts.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• adjective aiding and abetting in a crime
• noun someone who helps another person commit a crime
• adjective furnishing added support
• noun clothing that is worn or carried, but not part of your main clothing
• noun a supplementary component that improves capability