In describing the relationship of a complex unit to its linguistic environment, we use the convenient dichotomy of endocentric vs. exocentric. We say, for example, that 'applesauce' and 'blackbird' are structurally endocentric because the complex forms have substantially the same linguistic distribution as the head constituents '-sauce' and '-bird'. Similarly, we say that 'entertainment', 'up-set', and 'set-up' are exocentric because the distribution of these forms is different from that which the head constituents 'entertain' and 'set' possess.
- Nida (1951), a pag.12

The phrase 'black bird' is structurally and semantically endocentric, but the compound 'black-bird', tho structurally still endocentric, is semantically exocentric, since it identifies a class of birds, which, tho black, do not include all black birds, e.g. 'crows'.
- Nida (1951), a pag.12