thumb

UK: /ˈθʌm/ US: /θʌm/ ,(thum)

WordReference Random House Learner's Dictionary of American English © 2025

thumb /θʌm/   n. 

1. Anatomy the short, thick, inner digit of the hand, next to the forefinger and set apart from the other four:
   [countable] He stuck out his thumb for a ride.
2. Zoology the corresponding finger in animals.
3. the part of a glove or mitten that contains this digit.

v. 

4. to turn (pages) with the thumb:
   [~ + object] to thumb the edges of a book.
5. to glance through (pages):
   [~ + through + object] thumbed through the brochure.
6. (of a hitchhiker) to ask for (a ride) by pointing the thumb in the direction of travel:
   [~ + object] to thumb a ride.

Idioms

7. Idioms be all thumbs, to be clumsy:
   When it comes to car repairs he's all thumbs.
8. Idioms thumb one's nose, [~ + at + object]
   • to raise the hand with fingers extended and touch the thumb to the nose as a gesture of contempt, etc.:
     thumbed his nose at the police officer and raced off.
   • to show contempt or defiance:
     to thumb one's nose at society.
9. under someone's thumb, to be under the control or rule of someone else.

WordReference Random House Unabridged Dictionary of American English © 2025

thumb (thum),  n. 

1. Anatomy the short, thick, inner digit of the human hand, next to the forefinger.
2. Zoology the corresponding digit in other animals;
   pollex.
3. the part of a glove or mitten for containing this digit.
4. Architecture an ovolo or echinus molding.
5. all thumbs, awkward;
   clumsy;
   bungling:
   The visitor almost knocked over a vase and seemed to be all thumbs.
6. thumbs down, a gesture or expression of dissent or disapproval:
   We turned thumbs down to that suggestion.
7. thumbs up, a gesture or expression of assent or approval.
8. under one's thumb, under the power or influence of;
   subordinate to. Also, under the thumb of. 

v.t. 

9. to soil or wear with the thumbs in handling, as the pages of a book.
10. to glance through (the pages of a book, leaflet, etc.) quickly.
11. to play (a guitar or other instrument) with or as with the thumbs.
12. (of a hitchhiker) to solicit or get (a ride) by pointing the thumb in the desired direction of travel.
13. thumb one's nose:
    • to put one's thumb to one's nose and extend the fingers as a crudely defiant or contemptuous gesture.
    • to express defiance or contempt;
      dismiss or reject contemptuously.

• bef. 900; Middle English; Old English thūma; cognate with Dutch duim, Old Saxon, Old High German dūmo (German Daumen), Old Norse thumall; akin to Latin tumēre to swell (tumor)

thumb′less, adj. 
thumb′like′, adj. 

Collins Concise English Dictionary © HarperCollins Publishers::

thumb / θʌm/ noun

1. the first and usually shortest and thickest of the digits of the hand, composed of two short bones
2. the corresponding digit in other vertebrates
3. the part of a glove shaped to fit the thumb
4. all thumbs ⇒ clumsy
5. thumbs down ⇒ an indication of refusal, disapproval, or negation: he gave the thumbs down on our proposal
6. thumbs up ⇒ an indication of encouragement, approval, or acceptance
7. under someone's thumb ⇒ at someone's mercy or command

verb

1. (transitive) to touch, mark, or move with the thumb
2. to attempt to obtain (a lift or ride) by signalling with the thumb
3. when intr, often followed by through: to flip the pages of (a book, magazine, etc) perfunctorily in order to glance at the contents
4. thumb one's nose at ⇒ to deride or mock, esp by placing the thumb on the nose with fingers extended

Etymology: Old English thūma; related to Old Saxon thūma, Old High German thūmo, Old Norse thumall thumb of a glove, Latin tumēre to swell