millpond

noun

1. A pond or reservoir produced by damming a river or stream in order to provide a steady source of water for a millrace.

   “When I came to the saw-mill at Brække, the sky was overcast, it was already growing dark, only above the level of the north-western horizon there appeared a streak of light, which threw a subdued glimmer on the tranquil surface of the mill-pond.”