A brier is a wild bush with sharp thorns — the tangled, scratchy growth you find in a hedge or on a hillside, the kind that catches your clothes and your skin. Brambles and wild roses belong to this picture. In everyday talk the word can sound a little old; many people now just say thorn bush or bramble. You still meet brier in stories, poems, and older books. There is a second, more special use: the root of a Mediterranean bush (also called brier, or briar) is carved into tobacco pipes. A brier pipe is that kind of pipe. You will see the spelling briar just as often — they are the same word. Briar is the more common spelling in American English; brier turns up a lot in British writing. So: a thorny wild bush, and also the wood (and the pipe) made from that other bush’s root.