tram·a·dol (tr?m??-dôl?)n. A synthetic analgesic, C16H25NO2, used in its hydrochloride form to treat moderate to moderately severe pain. It is structurally similar to codeine and has both opioid and nonopioid effects.[tram-, of unknown origin + -adol, mixed opiate agonist/antagonist suffix.]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.