1) Conduit 2) Reservoir outlet 3) Spill 4) Surplus-water passage 5) Wasteweir 1) Damcontrol 2) Shaft 3) Wasteweir 
A spillway is a structure used to provide the controlled release of flows from a dam or levee into a downstream area, typically being the river that was dammed. In the UK they may be known as overflow channels. Spillways release floods so that the water does not overtop and damage or even destroy the dam. Except during flood periods, water does no...
• (n.) A sluiceway or passage for superfluous water in a reservoir, to prevent too great pressure on the dam.
A constructed passage for surplus water to run over or around a dam.
passage for surplus water over or around a dam when the reservoir itself is full. Spillways are particularly important safety features for earth ... [1 related articles]
see EMBRASURE.
A passage for surplus water to flow over or around a dam.
Spill'way` noun A sluiceway or passage for superfluous water in a reservoir, to prevent too great pressure on the dam. 
Type: Term Pronunciation: spil′wā Definitions: 1. A groove or channel through which food may pass from the occlusal surfaces of teeth during the masticatory process. Synonyms: sluiceway
[n] - a channel that carries excess water over or around a dam or other obstruction
a structure or channel designed to release water from behind a dam
spill noun a channel that carries excess water over or around a dam or other obstruction
A passage for surplus water to flow over or around a dam.