1. 1. The short thick digit of the human hand, next to the index finger and opposable to each of the other four digits.
   2. A corresponding digit in other animals, especially primates. Also called pollex.
2. The part of a glove or mitten that covers the thumb.
3. Architecture. An ovolo.

1. To scan (written matter) by turning over pages with or as if with the thumb.
2. To disarrange, soil, or wear by careless or frequent handling.
3. Informal. To solicit (a ride) from a passing vehicle by signaling with the thumb.

1. To scan written matter by turning over pages with or as if with the thumb: thumbed through the latest issue of the magazine.
2. Informal. To hitchhike.

all thumbs

1. Lacking physical coordination, skill, or grace; clumsy.

1. To express scorn or ridicule by or as if by placing the thumb on the nose and wiggling the fingers.

1. An expression of rejection, refusal, or disapproval.

1. An expression of approval, success, or hope.

1. Under the control of someone; subordinate to.

[Middle English, from Old English thūma.]

The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.