1. interjection
A shouted warning that something is falling from above, mind your heads.
2. noun
a) That part of older sailing ships forward of the forecastle and around the beak, used by the crew as their lavatory; still used as the word for toilets on a ship.<!encyclopedic info irrelevant to the definition:
Heads, I win.
b) The side of a coin that bears the picture of the head of state or similar
Pass me the heads, I wanna listen.
Wikipedia foundation.