in the sea-language, a long piece of timber with which the clew of the fudding-tail is spread out; and sometimes the boom is used to spread or boom out the clew of the mainmast.

Boom-spars, imported from the British plantations, are free; if from Ireland, Asia, or Africa, they pay 6s. 5d. the hundred; and if from elsewhere, 9s. 6½d.

Boom denotes also a cable stretched athwart the mouth of a river or harbour; with yards, topmasts, battling or spars of wood lashed to it, to prevent an enemy's coming in.