Definition of apetalous in US English:

apetalous

adjective

Botany
  • (of a flower) having no petals.

    • ‘Flowers are small, with white petals up to 2.5 mm or often apetalous, and last only a short time.’
    • ‘The flower is apetalous with deciduous sepals.’
    • ‘Morphological characters include leaves that are not gland-dotted, persistent intrapetiolar stipules, some apetalous species, and a reduction in stamen number in several species.’
    • ‘Flowers in both species are apetalous, with short, inconspicuous calyx lobes and no nectaries.’

Origin

Early 18th century: from modern Latin apetalus, from Greek apetalos ‘leafless’ (from a- ‘without’ + petalon ‘leaf’) + -ous.

Pronunciation

apetalous

/ˌāˈpedələs/