A group of words which have a different meaning when used together from the one they would have if you took the meaning of each word separately.
talk something out
to settle something by discussion.
Let's not get mad. Let's just talk it out.
Phrasal verbs, also called two-word verbs, are idiomatic expressions wherein the second element of the verb (the adverb or particle) is not necessarily predictable.
A compilation of 50 phrasal verbs.