Fat Finger

A "Fat Finger" is when one presses a key that they didn't mean to press, aka a typo when entering an order. For example, Dan may say "I am placing an order for 79.9 on $FSLR" and once he gets filled he says "Shoot! I fat fingered, I actually entered FSLY 79.5, I meant to put it in for 79.9."

A fat finger error is a human error caused by pressing the wrong key when using a computer to input data. Fat finger errors are often harmless but can sometimes have a significant market impact. (Investopedia)