The noun thumb has 3 senses (first 1 from tagged texts)
1. (5) thumb, pollex -- (the thick short innermost digit of the forelimb)
2. thumb -- (the part of a glove that provides a covering for the thumb)
3. ovolo, thumb, quarter round -- (a convex molding having a cross section in the form of a quarter of a circle or of an ellipse)
Overview of verb thumb
The verb thumb has 3 senses (first 1 from tagged texts)
1. (2) hitchhike, hitch, thumb -- (travel by getting free rides from motorists)
2. flick, flip, thumb, riffle, leaf, riff -- (look through a book or other written material; "He thumbed through the report"; "She leafed through the volume")
3. finger, thumb -- (feel or handle with the fingers; "finger the binding of the book")