Definition: The short thick digit of the hand that for humans has the most mobility and can be made to oppose (moved to touch) all of the other fingers.

Alright class, settle down, let’s take a look! We’ve got a tricky word today, “thumbs,” you see. The dictionary tells us, quite clearly, it’s meant for you and me! It says our thumb's a digit, short and stout, With plenty of movement, no room for doubt! Think about your hand, give it a little wave, This special finger’s ready to behave. It can “oppose” the others, that’s the key, you know, Moving towards each finger, putting on a show! It’s the most mobile one, so nimble and bright, Helping us grasp and hold with all its might! So "thumbs" means this clever little friend, A crucial part of your hand until the very end! Do you have any questions about this little thumb? Let's discuss!