tenonPronunciation: /ˈtɛnən/Definition of tenon noun a projecting piece of wood made for insertion into a mortise in another piece. verb [with object] join by means of a tenon:the rail was tenoned into oak stiles cut as a tenon: the part to be tenoned is wider than the part to be mortisedDerivatives tenoner noun Origin: late Middle English: from French, from tenir 'to hold', from Latin teneretenon in other Oxford dictionaries Definition of tenon in the US English dictionary