That which adds or supplements. That which contributes, e.g. contributory negligence.
Law Dictionary – Alternative Legal Definition
(noun) – A person liable to contribute to the assets of a company which is being wound up, as being a member or (in some cases) a past member thereof. Mozley A Whitley.
(adjective) – Joining in the promotion of a given purpose; lending assistance to the production of a given result. As to contributory “Infringement” and “Negligence,” see those titles.