adj

• (law) Assisting a crime without actually participating in committing the crime itself; being connected as an incident or subordinate to a principal.
  "Her actions were clearly accessory because they helped him commit and probably also conceal the crime."

noun

• (fashion) An article that completes one's basic outfit, such as a scarf or gloves.
  "One of the first of a wave of American women contemporary designers who emerged in the 1990s, she [Kate Spade] built a brand on the appeal of clothes and accessories that made shoppers smile."
• (law) A person who is not present at a crime, but contributes to it as an assistant or instigator.
  "She was an accessory to the murder because she helped him commit and probably also conceal the crime."
• (art) Something in a work of art without being indispensably necessary, for example solely ornamental parts.