IS A Condition

IS A Condition is a condition proposed by Allen (1978) to express two salient facts about compounds: (a) the syntactic category of a compound is determined by its rightmost member, (b) the meaning of a compound is contained in the meaning of its rightmost member.

Example
the English compound houseboat is a noun as is boat, and a houseboat is a kind of boat. The Is A Condition is the predecessor of Williams' (1981a) Righthand Head Rule.

Link
Utrecht Lexicon of Linguistics