n. 水闸门, 水道, 水渠

[机] 压力水管, 导水管

Penstock \Pen"stock\, n. [Etymol. uncertain; perh. fr. pen an
inclosure + stock.]
1. A close conduit or pipe for conducting water, as, to a
water wheel, or for emptying a pond, or for domestic uses.

2. The barrel of a wooden pump.