From WordNet (r) 2.0 [wn]:
From Moby Thesaurus II by Grady Ward, 1.0 [moby-thes]:
37 Moby Thesaurus words for "underpass": access, aisle, alley, ambulatory, aperture, arcade, artery, avenue, channel, cloister, colonnade, communication, conduit, connection, corridor, covered way, defile, exit, ferry, ford, gallery, inlet, interchange, intersection, junction, lane, opening, outlet, overpass, pass, passage, passageway, portico, railroad tunnel, traject, trajet, tunnel
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