A bright colour is strong and noticeable, and not dark.

A bright light, object, or place is shining strongly or is full of light.

If you describe someone as bright, you mean that they are quick at learning things.

A bright idea is clever and original.

If someone looks or sounds bright, they look or sound cheerful and lively.

If the future is bright, it is likely to be pleasant or successful.

The brights on a car or other vehicle are the headlights when they are switched on fully.

If you look on the bright side, you try to be cheerful about a bad situation by thinking of some advantages that could result from it, or thinking that it is not as bad as it could have been.