tunnel Synonyms

burrow shaft shovel sink underground passage spade subterranean subterraneous subway sewer sett scoop sap quarry pit pipette pipe penetrate thill tideway tube slit trench underpass gouge out crawlway hollow out mineshaft stave in pipeline scoop out dig out whetstone warren viaduct undermine tunnelling tunneling passageway passage den delve crosscut coupure conduit chimney channel cavern cave cannula canal