home platen. Baseball A base, usually consisting of a hard rubber slab, at one of the corners of a diamond at which a batter stands when hitting and which a base runner must finally touch in order to score.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.home plate n (Baseball) baseball a flat often five-sided piece of hard rubber or other material that serves to define the area over which the pitcher must throw the ball for a strike and that a base runner must safely reach on his way from third base to score a run. Also called: plate, home or home base Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014home? plate? n. the base in baseball at which the batter stands and which a base runner must reach safely in order to score a run, typically a slab of rubber set at the front corner of the diamond. Random House Kernerman Webster’s College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.home plateSlab of whitened rubber sunk into the ground in front of the catcher.Dictionary of Unfamiliar Words by Diagram Group Copyright © 2008 by Diagram Visual Information Limited