- In linguistics co-occurence can be either concurrence/coincidence or, in a more specific sense, the frequent occurrence of two terms from a text corpus alongside each other in a certain order. Therefore it can be interpreted as an indicator of semantic proximity or an idiomatic expression, and contrary to collocation, co-occurrence assumes interdependency of the two terms. More on co-occurence here. Collocation is defined as a sequence of words or terms which co-occur more often than would be expected by chance. More on collocation here.