Rhopalic :: Rhopalic (a.) Applied to a line or verse in which each successive word has one more syllable than the preceding.
Rhopalium :: Rhopalium (n.) One of the marginal sensory bodies of medusae belonging to the Discophora.
Rhopalocera :: Rhopalocera (n. pl.) A division of Lepidoptera including all the butterflies. They differ from other Lepidoptera in having club-shaped antennae.