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 word… - John Rupert Firth

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.

Strictly speaking, the grammatical method of resolving a sentence into parts is nothing but a fanciful procedure ; but it is the real fountain of all knowledge, since it led to the invention of writing.

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