a thin flat piece of cloth, paper, skin etc that is fixed by one edge to a surface, which you can lift up easily: ➔ cat flap
flat piece of something[countable]
the tent flap
A loose flap of skin covered the wound.
the noisy movement of something such as cloth in the air:
the flap of the sails
a situation in which people feel very excited or worried about something
be in a flap➔ unflappable
Rafi's in a bit of a flap over the wedding plans.
a part of the wing of an aircraft that can be raised or lowered to help the aircraft go up or down