tricyclic antidepressant

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun Any of a group of antidepressant drugs, such as amitryptyline, that contain three fused benzene rings and that block the reuptake of the neurotransmitters norepinephrine and serotonin in the central nervous system.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun an antidepressant drug that acts by blocking the reuptake of norepinephrine and serotonin and thus making more of those substances available to act on receptors in the brain