From The Collaborative International Dictionary of English v.0.48:
Wether \Weth"er\, n. [OE. wether, AS. we[eth]er; akin to OS.
wethar, withar, a ram, D. weder, G. widder, OHG. widar, Icel.
ve[eth]r, Sw. v[aum]dur, Dan. v[ae]dder, Goth. wi[thorn]rus a
lamb, L. vitulus calf, Skr. vatsa, L. vetus old, Gr. 'e`tos
year; -- originally meaning, a yearling. Cf. Veal,
Veteran.]
A castrated ram.
[1913 Webster]