Collocations or compounds

[Rachel Adams]

This screenshot is from the book "English Collocations in Use" by Michael McCarthy and Felicity O'Dell.
It says "car park" and "post office" are compounds but "fast food" and "fast car" are collocations. In the definition of collocations I read that compounds consist of two or more words and collocations consist of two or more words that form a phrase. These collocations like compounds consist of two words and they don't form a phrase. How do I understand the difference between them?


I will try to answer my own question. Compound nouns are a combination of words that function as a single unit of meaning. Thus, "post office", "car park" consist of different words but together they create a different meaning. They are compounds.

"Fast car" and "fast food" are examples of how different words go together so they are collocations.

 

[Tdol]

I honestly wouldn't worry about the distinction. However, I disagree with them a bit- fast food has connotations that go beyond speed, with many people associating it with unhealthy lifestyles and convenience, so it is not exactly the same as driving a Ferrari.