Examples of definitions from the Collins COBUILD English Dictionary

Here are interesting examples of definitions from the Collins COBUILD Advanced Learner's English Dictionary with our comments:

If someone or something is unaffected by an event or occurrence, they are not changed by it in any way.

This definition shows the typical grammar structure in which we use the word unaffected — after a form of be (is, was, will be, etc.), and before the preposition by. So it tells you that we often say "is unaffected by", "was unaffected by", "will be unaffected by", etc. It also shows that people or things can be unaffected by an event.

You say that something is stupid to indicate that you do not like it or that it annoys you.

The beginning of this definition ("You say that...") shows that you use the word stupid to talk about your feelings, and not about facts. If you say to somebody "You're stupid", you don't mean that the person is not intelligent. You simply mean that you don't like them.

In tennis, an ace is a serve which is so fast that the other player cannot reach the ball.

This is the definition of one of the meanings of ace. It gives you the context of this meaning — it tells you that you use it when talking about tennis.