[trahy-sahy-klik, -sik-lik]
  1. Also called tricyclic antidepressant. Pharmacology. any of a group of pharmacologically active substances, as imipramine, that share a common three-ring structure, used to treat depression and cocaine abuse.

Origin of tricyclic

First recorded in 1890–95; tri- + cyclic Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

British Dictionary definitions for tricyclic antidepressant


  1. (of a chemical compound) containing three rings in the molecular structure
  1. an antidepressant drug having a tricyclic molecular structure
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

tricyclic antidepressant in Medicine

tricyclic antidepressant

[trī-sīklĭk, -sĭklĭk]
  1. Any of a class of antidepressants, such as amitriptyline, that are structurally related to the phenothiazine antipsychotics.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

tricyclic antidepressant in Science


[trī-sīklĭk, -sĭklĭk]
  1. Relating to a chemical compound having three closed rings. Anthracene is a tricyclic hydrocarbon.
  2. Relating to a class of drugs used to treat depression and having a tricyclic chemical structure consisting of two benzene rings fused to opposite sides of a seven-member ring. The seven-member ring consists of six carbon atoms and one nitrogen atom. Tricyclic antidepressants enhance the activity of monoamine neurotransmitters in the brain by inhibiting their reuptake by the cells that secrete them.
  3. Composed of or arranged in three distinct whorls, as the petals of a flower.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.