thumb

American  

[thuhm] / θʌm /

noun

1. the short, thick, inner digit of the human hand, next to the forefinger.

2. 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.

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verb (used with object)

1. to soil or wear with the thumbs in handling, as the pages of a book.

2. to glance through (the pages of a book, leaflet, etc.) quickly.

3. to play (a guitar or other instrument) with or as with the thumbs.

4. (of a hitchhiker) to solicit or get (a ride) by pointing the thumb in the desired direction of travel.

idioms

1. thumbs up, a gesture or expression of assent or approval.

2. under one's thumb, under the power or influence of; subordinate to. Also under the thumb of.

3. thumb one's nose,

   1. to put one's thumb to one's nose and extend the fingers as a crudely defiant or contemptuous gesture.

   2. to express defiance or contempt; dismiss or reject contemptuously.

4. thumbs down, a gesture or expression of dissent or disapproval.

   We turned thumbs down to that suggestion.

5. all thumbs, awkward; clumsy; bungling.

   The visitor almost knocked over a vase and seemed to be all thumbs.

thumb British  

/ θʌm /

noun

1. Technical name: pollex.  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. architect another name for ovolo

5. clumsy

6. an indication of refusal, disapproval, or negation

   he gave the thumbs down on our proposal

7. an indication of encouragement, approval, or acceptance

8. at someone's mercy or command

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verb

1. (tr) to touch, mark, or move with the thumb

2. to attempt to obtain (a lift or ride) by signalling with the thumb

3. to flip the pages of (a book, magazine, etc) perfunctorily in order to glance at the contents

4. to deride or mock, esp by placing the thumb on the nose with fingers extended

thumb More Idioms  

More idioms and phrases containing thumb

• all thumbs
• green thumb
• rule of thumb
• stick out (like a sore thumb)
• twiddle one's thumbs
• under someone's thumb

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Other Word Forms

• thumbless
  adjective
• thumblike
  adjective

Etymology

Origin of thumb

before 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 )

Explanation

Your thumb is the fifth digit on your hand, the one that doesn't quite match your fingers. Thumbs help us grip objects with care and precision — it would be difficult to hold chopsticks without a thumb. Humans are more dextrous than our closest primate relatives because of our nimble thumbs. They're opposable, so we can move them forward and touch them to our fingers. Some monkeys share this trait, and they're the best able to use primitive tools. Your thumbs make it possible for you to brush your teeth, write with a pen, and snap. You can also thumb through the pages of a book — in other words, turn each page with your thumb.

Example Sentences

There’s no real rule of thumb for this, other than that it’s always best to keep your immediate cash needs liquid in a high-yield savings account or money-market account.

From MarketWatch • May 11, 2026

France has vowed to abandon the so‑called "Francafrique" strategy, under which Paris sought to keep francophone Africa under its thumb through political collusion, exclusive access for French businesses and oblique financial deals, including graft.

From Barron's • May 10, 2026

To recap, three simple rules of thumb can help you think through financial decisions:

From The Wall Street Journal • May 9, 2026

He explained that “I’ve spent the past decade making sure our party cannot ever again be perceived as having a thumb on the scale for one candidate.”

From Salon • May 5, 2026

He plucks out a blade of grass with his free hand and spins it between the pads of his thumb and index finger.

From "Keeping Pace" by Laurie Morrison

Related Words

• brush
• caress
• feel
• handle
• hit
• kiss
• lick
• pat
• reach
• rub
• strike
• stroke
• tap