In Linguistics, an endocentric construction is one that fulfills the same grammatical role as one of its constituents. For example, if a Zoo has a "lion house", that Phrase is endocentric since it functions as a Noun, as are its two constituent words.
More formally, an endocentric construction is one whose distribution is functionally equivalent, or approaching equivalence, to one of its constituents, which serves as the centre, or head, of the whole. Hence an endocentric construction is also known as a headed construction.