Collocations are actual words in habitual company. A word in a usual collocation stares you in the face just as it is. Colligations cannot be of words as such. Colligations of grammatical categories related in a grammatical structure do not necessarily follow word divisions or even sub-divisions of words.

Firth (1962, p. 14), as cited in Wendy J. Anderson, A corpus linguistic analysis of phraseology and collocation in the register of current European Union administrative French. Diss. University of St Andrews, 2003.