pollex?


from etymonline:

Quote:

thumb
O.E. žuma, from W.Gmc. *thuman- (cf. O.Fris. thuma, O.S., O.H.G. thumo, Ger. Daumen, Du. duim "thumb," O.N. žumall "thumb of a glove"), lit. "the stout or thick (finger)," from PIE *tum- "swell" (cf. L. tumere "to swell," tumidus "swollen;" Avestan tuma "fat;" see thigh).


formerly known as etaoin...