n A rigid tube that transports water, steam(,) or other fluid, as used in plumbing and numerous other applications.
n (context|smoking) A hollow stem with bowl at one end used for smoking, especially a tobacco pipe but also including various other forms such as a water pipe.
n (geology) A vertical conduit through the Earth's crust below a volcano, through which magma has passed; often filled with volcanic breccia
n (obsolete) An English measure of capacity for liquids, containing 126 wine gallons; half a tun.
n (Australia|colloquial|obsolete) An anonymous satire or essay, insulting and frequently libelous, written on a piece of paper and left somewhere public where it could be found and thus spread, to embarrass the author's enemies.
n (idiomatic|slang) A man's penis
v (transitive) To convey or transport (something) by means of pipes.
v (transitive) To install or configure with pipes.
v (intransitive) To play music on a pipe instrument, such as a bagpipe.
v (nautical) To signal or order by a note pattern on a bosun's pipe.
v (transitive|figuratively) To lead or conduct as if by pipes, especially by wired transmission.
v (transitive|computing|chiefly|Unix) To directly feed (the output of one program) as input to another program, indicated by the pipe character at the command line.