watch nightn.1. New Year’s Eve.2. A religious service held on New Year’s Eve.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.watch night (in Protestant churches) n1. (Protestantism) a. the night of December 24, during which a service is held to mark the arrival of Christmas Dayb. the night of December 31, during which a service is held to mark the passing of the old year and the beginning of the new2. (Protestantism) the service held on either of these nightsCollins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014watch? night` n. 1. the last night of the year. 2. a religious service held on this night. [1735?45] Random House Kernerman Webster’s College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.