an instrumentality invented for a particular purpose

an instrument that performs analyses

an instrument or substance used to destroy tissue for medical reasons (eg removal of a wart) by burning it with a hot iron or an electric current or a caustic or by freezing it

an instrument used by a draftsman in making drawings

an instrument or machine that is used in warfare, such as a battering ram, catapult, artillery piece, etc.

an instrument for extracting tight-fitting components