The complete meaning of a word is always contextual, and no study of meaning apart from context can be taken seriously. - John Rupert Firth

You shall know a word by the company it keeps.

It is not easy to determine what are the units of speech. Some would say speech sounds, others phonemes... The general opinion is, however, that words, not phones or phonemes or phoneme systems, are the units of speech.

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.