ait (?t)n. Chiefly British A small island.[Middle English eit, from Old English ?geth, diminutive of ?g, ?eg, island; see island.]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.ait (e?t) or eyotndialect an islet, esp in a river[Old English ?gett small island, from ieg island]Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014ait (e?t) n. Brit. a small island, esp. in a river. [before 900; Middle English eyt, Old English ?gett, diminutive of ieg, ?g island. See island] Random House Kernerman Webster’s College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.eyot, ait – A small island in a river or lake is an eyot or ait.See also related terms for lake.Farlex Trivia Dictionary. © 2012 Farlex, Inc. All rights reserved.