POLLEX
thumb, pollex
(noun) the thick short innermost digit of the forelimb
Source: WordNet® 3.1
Etymology
Noun
pollex (plural pollices)
The thumb; the first, or preaxial, digit of the forelimb, corresponding to the hallux in the hind limb. In birds, the pollex is the joint which bears the alula or bastard wing.
Source: Wiktionary
Pol"lex, n.; pl. Pollices. Etym: [L., the thumb.] (Anat.)
Definition: 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: Webster’s Unabridged Dictionary 1913 Edition