a slow pitch that moves erratically toward home plate, usually delivered by holding the ball between the thumb and the knuckles of the first joints of the first two or three fingers.
- knuckle down,
- knuckle joint,
- knuckle pads,
- knuckle sandwich,
- knuckle under
Origin of knuckle ball
An Americanism dating back to 1905–10
Also called knuck·ler [nuhk-ler] /ˈnʌk lər/.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
Online Etymology Dictionary, © 2010 Douglas Harper