What's the difference between a phrasal verb and a collocation?
By definition, phrasal verbs are collocations (two or more words that “go together”), but not all collocations are phrasal verbs.
A collocation is a general term referring to words that usually or always go together. A collocation can perform various functions in a sentence (i.e. act as different parts of speech). Some examples are “bunch of flowers” or “commit a crime.”
A phrasal verb is usually a combination of a verb + a preposition which usually changes the meaning from that of the original verb. For example, “put + up with” means to tolerate, while “put + up” means to return something to its original/proper position (especially when cleaning), and “put + off” means to delay doing something until a later time.
The preposition part of the phrasal verb changes the entire meaning, so it’s good to memorize certain phrasal verbs in chunks of verb+prep instead of just learning the definition of the verb, and then the preposition separately.