From Oxford English Dictionary, 2d edition:


webster1 [we.bst<e>r]
Obs. exc. Hist. Forms: 2 webbestre, 4 web(b)ester, webister, 4-5 webstere, 5 webstar, 6 wyebster, 3- webster; Sc. 5-6 wobstar, 6-7 wobster, 6- wabster.
OE. webbestre, fem.of webba weaver.

A weaver:
a. as the designation of a woman.
b. extended, or applied spec., to a male weaver.