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.

Definitions of thumb
  1. noun
    the thick short innermost digit of the forelimb
    synonyms: pollex
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    type of:
    any of the terminal members of the hand (sometimes excepting the thumb)
  2. noun
    the part of a glove that provides a covering for the thumb
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    type of:
    an artifact that covers something else (usually to protect or shelter or conceal it)
  3. verb
    look through a book or other written material
    “He thumbed through the report”
    synonyms: flick, flip, leaf, riff, riffle
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    type of:
    examine or consider with attention and in detail
  4. verb
    feel or handle with the fingers
    synonyms: finger
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    type of:
    make physical contact with, come in contact with
  5. verb
    travel by getting free rides from motorists
    synonyms: hitch, hitchhike
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    type of:
    be carried or travel on or in a vehicle
  6. noun
    a convex molding having a cross section in the form of a quarter of a circle or of an ellipse
    synonyms: ovolo, quarter round
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    ovolo molding between the shaft and the abacus of a Doric column
    type of:
    molding, moulding
    a decorative strip used for ornamentation or finishing
Word Family
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