Definition of pipe :
1. A boatswain's whistle, used to call the crew to their duties; also, the sound of it.
2. A cask usually containing two hogsheads, or 126 wine gallons; also, the quantity which it contains.
3. A passageway for the air in speaking and breathing; the windpipe, or one of its divisions.
4. A roll formerly used in the English exchequer, otherwise called the Great Roll, on which were taken down the accounts of debts to the king; - so called because put together like a pipe.
5. A small bowl with a hollow steam, - used in smoking tobacco, and, sometimes, other substances.
6. A wind instrument of music, consisting of a tube or tubes of straw, reed, wood, or metal; any tube which produces musical sounds; as, a shepherd's pipe; the pipe of an organ.
7. An elongated body or vein of ore.
8. Any long tube or hollow body of wood, metal, earthenware, or the like: especially, one used as a conductor of water, steam, gas, etc.
9. The bagpipe; as, the pipes of Lucknow.
10. The key or sound of the voice.
11. The peeping whistle, call, or note of a bird.
12. To become hollow in the process of solodifying; - said of an ingot, as of steel.
13. To call or direct, as a crew, by the boatswain's whistle.
14. To call, convey orders, etc., by means of signals on a pipe or whistle carried by a boatswain.
15. To emit or have a shrill sound like that of a pipe; to whistle.
16. To furnish or equip with pipes; as, to pipe an engine, or a building.
17. To perform, as a tune, by playing on a pipe, flute, fife, etc.; to utter in the shrill tone of a pipe.
18. To play on a pipe, fife, flute, or other tubular wind instrument of music.
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conduit (part of speech: noun)
musical instruments (part of speech: noun)