Thumb (noun)

The short, thick finger on the hand which is opposite to the four fingers.

Origin:

From the old english word "þuma" meaning the thickest and shortest finger on the hand, it refers to the short, thick finger on the hand which is opposite to the four fingers.

Examples:

1. The carpenter held the hammer with his thumb and index finger.
2. The musician placed her thumb on the guitar's fretboard to play a chord.
3. The child held the pencil with his thumb and fingers.
4. The hitchhiker stuck out his thumb to signal for a ride.
5. The doctor examined the patient's thumb for any injuries.