channel has 19 distinct synonyms spread across 8 of its 11 senses. Each sense below keeps its own list, because a synonym belongs to a meaning and not to a word: swapping one sense's substitute into another sense's sentence is how a thesaurus makes writing worse. WordNet records no antonym for it — antonymy is a relation between word forms rather than concepts, so it is deliberately sparse.
Counts are distinct word forms across every sense. A synonym that appears under three senses is counted once here and shown three times below, under each sense it belongs to.
a path over which electrical signals can pass
“a channel is typically what you rent from a telephone company”
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
“the ship went aground in the channel”
(often plural) a means of communication or access
“it must go through official channels”
a bodily passage or tube lined with epithelial cells and conveying a secretion or other substance
“the tear duct was obstructed”
a television station and its programs
“a satellite TV channel”
a way of selling a company's product either directly or via distributors
“possible distribution channels are wholesalers or small retailers or retail chains or direct mailers or your own stores”
direct the flow of
“channel information towards a broad audience”
Synonyms, antonyms and the broader and narrower relations for channel come from Princeton University’s WordNet. Full sources and licences.