A more formal definition of Collocation given by Mel’čuk (1995, p. 179):
> A collocation **AB** of **L** is a semantic phraseme of L such that its signified ‘X” is constructed out of the signified of the one of its two constituent lexemes — say, of **A [...]** such that the lexeme **B** expresses ‘C” contingent on **A**.
~
LEMNITZER, Lothar and GEYKEN, Alexander, 2015. Semantic Modeling of Collocations for Lexicographic Purposes. Journal of Cognitive Science. 2015. Vol. 16, no. 3. pdf 
, p. 209.