forest

A forest is a large area covered with trees growing close together. Big enough to get lost in.

Size is what separates it from a wood, though nobody has fixed the line. English keeps some odd survivals from forest law, since a royal forest once meant land reserved for hunting whether it had trees on it or not, which is why the New Forest has open heath in it. The word works figuratively for anything dense and upright, as in a forest of masts or a forest of raised hands. The adjective is forested.