Exocentric constructions are those in which the unit as a whole belongs to a different external distribution class from the nuclear constituent or from both of the immediate constituents. [...] In the word 'income' the immediate constituents are an adverb 'in' and a verb 'come'; the resulting combination, being a noun, is exocentric, in that it does not belong too the class of either immediate constituents.
- Nida (1949), a pag.94