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knuckle ballor knuck·le·ball (nŭk′əl-bôl′)
A slow pitch that has almost no spin and veers erratically, thrown by gripping the ball with the nails or knuckles near the tips of the index and middle fingers, and often the third finger.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
a slow baseball pitch that moves erratically toward home plate, delivered by holding the ball between the thumb and the knuckles or fingertips.Also called knuck•ler (ˈnʌk lər)
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.