opposable thumb

/ ə-pō′zə-bəl /

1. A thumb that can be placed opposite the fingers of the same hand. Opposable thumbs allow the digits to grasp and handle objects and are characteristic of primates.

opposable thumb

1. A thumb that can be used for grasping.

Notes

Opposable thumbs are one of the distinguishing features of primates .

The opposable thumb of human beings allows us to use tools.

Example Sentences

It had the same place in crustacean development that the opposable thumb is believed to have had in that of man.

From Project Gutenberg

What a comedy that man should work so hard to prove that his chief glory is his opposable thumb, or a few ounces of brain matter!

From Project Gutenberg

What would man's power be as a tool-using animal without his strong, opposable thumb?

From Project Gutenberg