Source : Webster's Revised Unabridged Dictionary (1913)

Pollex \Pol"lex\, n.; pl. {Pollices}. [the thumb.] (Anat.)
   The first, or preaxial, digit of the fore limb, corresponding
   to the hallux in the hind limb; the thumb. In birds, the
   pollex is the joint which bears the bastard wing.

Source : WordNet®

pollex
     n : the thick short innermost digit of the forelimb [syn: {thumb}]
     [also: {pollices} (pl)]