sid·ed (s??d?d)adj. Having sides usually of a specified number or kind. Often used in combination: many-sided; marble-sided.sid?ed·ness 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.sid?ed (?sa? d?d) adj. having a specified number or kind of sides (usu. used in combination): five-sided; plastic-sided. [1425?75] Random House Kernerman Webster’s College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.