Collocation refers to words that are found together in language. Collocations can be fixed, where it is difficult to replace one of the words with an alternative, or freer, allowing for more choice of words.
'Utter disaster' is a fixed collocation, as there are few words that can be used instead of 'disaster'. 'Make a cake' is a freer collocation, as there are many words that can be used instead of 'cake'.
In the classroom
Collocations often have to be memorised; teachers can help learners focus on and remember collocations by exposing them to authentic texts, and by helping students to record collocations in their notebooks.