Select the most appropriate meaning of the given idiom.
Once in a blue moon
Answer & explanation
Correct answer: option 3
The most appropriate meaning of the idiom "once in a blue moon" is happening only rarely.
The idiom refers to something that happens very infrequently. It is often used to describe something that is so rare that it is almost impossible to happen.
For example, you might say that something happens "once in a blue moon" if it happens only once or twice a year.