Definition of tetracyclic in US English:

tetracyclic

adjective

Chemistry
  • (of an organic compound) having four fused rings of atoms in its molecule.

    • ‘Maprotiline is the only tetracyclic antidepressant available in the US.’
    • ‘Mirtazapine is a tetracyclic antidepressant unrelated to tricyclic antidepressants and SSRIs.’
    • ‘Practitioners prescribing the tetracyclic antibiotics should be aware of the syndrome of increased intracranial pressure, and pay particular attention to the ocular fundus for papilloedema.’
    • ‘A 1998 study showed that pentacyclic alkaloids weakly activated human B- and T-lymphocytes, and that tetracyclic oxindole alkaloids reduced the activity of pentacyclic oxindoles.’
    • ‘Cucurbitacins are oxygenated tetracyclic triterpenes that have been shown to have emetic, antineoplastic, and cytotoxic effects on herbivores, resulting in feeding and oviposition deterrence and reduced growth of consumers.’

Origin

Early 20th century: from tetra- ‘four’ + Greek kuklos ‘circle’ + -ic.

Pronunciation

tetracyclic

/ˌtetrəˈsīklik/