standpipe

Webster's Dictionary (1913)

1. Engineering A vertical pipe, open at the top, between a hydrant and a reservoir, to equalize the flow of water; also, a large vertical pipe, near a pumping engine, into which water is forced up, so as to give it sufficient head to rise to the required level at a distance.

2. Steam Boiler A supply pipe of sufficient elevation to enable the water to flow into the boiler, notwithstanding the pressure of the steam. Knight, Edward Henry

Webster’s Revised Unabridged Dictionary (1913), from GCIDE 0.54