Boom

[1] Enhanced reverberation or resonance in an enclosed space at low frequencies.
[2] A long beam such as the top and bottom members of a built up girder.
[3] The main jib of a crane.
[4] A spar holding the lower part of a fore-and-aft sail.
[5] A spar attached to a yard to lengthen it
[6] A barrier of logs to prevent the passage of a vessel.
[7] A line of floating timbers used to florm a floating harbor.
[8] A pole marking a channel.
[9] A length of flexible tubing to contain an oil spillage.
[10] A long movable arm to carry a microphone or lamp above the action in film or televsion shooting.