“Once in a blue moon”
What it really means, explained simply for children who take language literally.
What the words say
Only when the moon turns blue in the sky.
What it really means
Something that happens very rarely.
Example
We eat ice cream for breakfast once in a blue moon.
Sayings like this one do not mean what the words say. For a child who reads language literally, common with hyperlexia and autism, that hidden second meaning can be confusing or even worrying. Our free Idiom Explainer shows the literal picture and the real meaning side by side, so the next saying meets curiosity instead of worry. It runs in your browser, nothing is sent anywhere.