{ Weir (wēr), Wear,} n. [OE. wer, AS. wer; akin to G. wehr, AS. werian to defend, protect, hinder, G. wehren, Goth. warjan; and perhaps to E. wary; or cf. Skr. vṛ to check, hinder. √142. Cf. Garret.] 1. A dam in a river to stop and raise the water, for the purpose of conducting it to a mill, forming a fish pond, or the like.
2. A fence of stakes, brushwood, or the like, set in a stream, tideway, or inlet of the sea, for taking fish.
3. A long notch with a horizontal edge, as in the top of a vertical plate or plank, through which water flows, — used in measuring the quantity of flowing water.