Definition of tricyclic in English:



  • (of a compound) having three rings of atoms in its molecule.

    • ‘In addition to monocyclic shoots, there are also bicyclic ones, and on the branches in the canopy top there are even tricyclic vegetative shoots.’
    • ‘Clomipramine was equal to desipramine and both tricyclic agents were superior to placebo for amelioration of hyperactivity.’
    • ‘Quinacrine is a planar tricyclic compound with structural similarities to DMMB, yet it does not absorb red light.’
    • ‘The danger of precipitating mania is reported to be greatest with tricyclic agents.’
    • ‘In addition, all methyl sulfone containing compounds in the tricyclic class are very poorly bioavailable.’


  • Any of a class of antidepressant drugs having molecules with three fused rings.

    • ‘However inspection of comparative studies in fall risk between SSRIs and tricyclics suggest these two antidepressant classes exhibit similar risks of fall.’
    • ‘Over half of the prescriptions were for the class antidepressants known as tricyclics, while four out of 10 were for SSRIs.’
    • ‘There are several new antidepressants which work in a different way from SSRIs and tricyclics.’
    • ‘Their effect on blood pressure can be worsened by taking them along with certain antidepressants, such as tricyclics.’
    • ‘The most commonly prescribed antidepressant medications include the tricyclics and selective serotonin reuptake inhibitors.’


Late 19th century: from tri- ‘three’ + Greek kuklos ‘circle’+ -ic.