T-ball also tee-ball (t??bôl?)n. A form of baseball played by young children in which the ball is not pitched but hit from a stationary position on top of a tee.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.T-ball (?ti?b?l) n. a modified form of baseball or softball in which the ball is batted off an adjustable pole or stand. [1975?80; tee2] Random House Kernerman Webster’s College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.