Found:

functor

**MORPHOLOGY: **a notion which DiSciullo & Williams adopt from
Categorial Grammar to express relationships between entities.
** EXAMPLE:** if one wishes to express the idea that *y* is the
sister of *x*, the property 'sister of' can be formalized by using a functor, say F, and write '*y*=F(*x*)'. See **Function composition**.

LIT. | Di Sciullo, A. M. and E. Williams (1987) |