'Spillway' definitions:

Definition of 'spillway'

From: WordNet
noun
A channel that carries excess water over or around a dam or other obstruction [syn: spillway, spill, wasteweir]

Definition of 'Spillway'

From: GCIDE
  • Spillway \Spill"way`\, n. A sluiceway or passage for superfluous water in a reservoir, to prevent too great pressure on the dam. [1913 Webster]

Synonyms of 'spillway'

From: Moby Thesaurus