[boom] 
| 1. | Nautical. any of various more or less horizontal spars or poles for extending the feet of sails, esp. fore-and-aft sails, for handling cargo, suspending mooring lines alongside a vessel, pushing a vessel away from wharves, etc. |
| 2. | Aeronautics.
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| 3. | a chain, cable, series of connected floating timbers, or the like, serving to obstruct navigation, confine floating timber, etc. |
| 4. | the area thus shut off. |
| 5. | Machinery. a spar or beam projecting from the mast of a derrick for supporting or guiding the weights to be lifted. |
| 6. | (on a motion-picture or television stage) a spar or beam on a mobile crane for holding or manipulating a microphone or camera. |
| 7. | to extend or position, as a sail (usually fol. by out or off). |
| 8. | to manipulate (an object) by or as by means of a crane or derrick. |
| 9. | to sail at full speed. |
| 10. | lower the boom, to take decisive punitive action: The government has lowered the boom on tax evaders. |
