the·a·ter·go·er (th???-t?r-g???r)n. One who attends the theater.the?a·ter·go?ing adj. & n.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.the?a?ter?go?er or the?a?tre?go?er (??i ? t?r?go? ?r, ??i?-) n. a person who goes to the theater, esp. often or regularly. [1870?75] Random House Kernerman Webster’s College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.