pipe [countable]

1

tube

 a tube through which a liquid or gas flows:

a water pipe

a frozen waste pipe

copper pipes

A pipe had burst in the kitchen and flooded the floor.

➔ drainpipe

 ; ➔ exhaust pipe

 at exhaust2 (2), windpipe

2

for smoking

a thing used for smoking tobacco, consisting of a small tube with a container shaped like a bowl at one end:

Dad was there, smoking his pipe.

pipe tobacco

3

music

a) a simple musical instrument like a tube, that you play by blowing ➔ panpipes

b) one of the metal tubes that air passes through when you play an organ

c) 

the pipes

bagpipes

4

 pipe dream

a hope, idea, plan etc that is impossible or will probably never happen:

In many parts of the country, democratic elections are simply a pipe dream.

5

 put/stick that in your pipe and smoke it

spoken used to say that someone must accept what you have just said, even though they do not like it

Definition from the Longman Dictionary of Contemporary English
Advanced Learner's Dictionary.