| Penstock 1. (n.) A close conduit or pipe for conducting water, as, to a water wheel, or for emptying a pond, or for domestic uses. 2. (n.) The barrel of a wooden pump. Thesaurus Entries aboideau, air lock, chute, dock gate, eaves trough, flood-hatch, floodgate, gate, guide, gutter, head gate, lock, lock gate, pentrough, shoot, sluice, sluice gate, tide gate, trough, water gate, weir |