Answer:

culvert

Answer	Crossword Clue
CULVERT	Drain
CULVERT	Causeway conduit
CULVERT	Underground drain

CULVERT	Arched drain.
CULVERT	Conduit.
CULVERT	Conduit under a road

Crossword

a puzzle consisting of a grid of squares and blanks into which words crossing vertically and horizontally are written according to clues.