a channel is typically what you rent from a telephone company
a passage for water (or other fluids) to flow through [例]
the fields were crossed with irrigation channels
gutters carried off the rainwater into a series of channels under the street
a long narrow furrow cut either by a natural process (such as erosion) or by a tool (as e.g. a groove in a phonograph record) [同] groove , channel
a deep and relatively narrow body of water (as in a river or a harbor or a strait linking two larger bodies) that allows the best passage for vessels [例]