culvert(n = noun.artifact) - a transverse and totally enclosed drain under a road or railway;
is a kind of drain, drainpipe, waste pipe

   A transverse drain or waterway of masonry under a road, railroad, canal, etc.; a small bridge. [1913 Webster]

culvert, n.
1 an underground channel carrying water across a road etc.
2 a channel for an electric cable.

Etymology:
18th c.: orig. unkn.

N  conduit, channel, duct, watercourse, race, head race, tail race, abito, aboideau, aboiteau, bito, acequia, acequiador, acequiamadre, arroyo, adit, aqueduct, canal, trough, gutter, pantile, flume, ingate, runner, lock-weir, tedge, vena, dike, main, gully, moat, ditch, drain, sewer, culvert, cloaca, sough, kennel, siphon, piscina, pipe, funnel, tunnel, water pipe, waste pipe, emunctory, gully hole, artery, aorta, pore, spout, scupper, adjutage, ajutage, hose, gargoyle, gurgoyle, penstock, weir, flood gate, water gate, sluice, lock, valve, rose, waterworks, pipeline, vascular.