The innermost digit of a forelimb, especially the thumb in primates.
- ‘All eusauropods, in contrast, are characterized by a shortened manus in which each digit bears two or fewer phalanges, and only the pollex bears an ungual.’
- ‘The forefeet and hindfeet have 3 large digits; the pollex and hallux are reduced in size or absent and the fifth finger is very small.’
- ‘The first dorsal has been found divided into two, one part going to the pollex and one to the index; this is a very rare anomaly, not occurring more often than once in 120 subjects.’
- ‘The eyes are usually very small, the feet are plantigrade and have five digits, and neither the hallux or pollex is opposable.’
- ‘Four clawed digits are found on each forefoot (the pollex or ‘thumb’ is small and bears a nail); the hind foot in most has five clawed digits (but sometimes the hallux or first toe has a nail).’
Mid 19th century: from Latin, literally thumb or big toe.