ageratum

UK: /ˌædʒəˈreɪtəm/ US: (aj′ə rā′təm, ə jer′ə-)

WordReference Random House Unabridged Dictionary of American English © 2025

ag•er•a•tum  (aj′ə rā′təm, ə jer′ə-), n. 

1. Plant Biology any of several composite plants of the genus Ageratum, esp. A. houstonianum, having heart-shaped leaves and small, dense, blue, lavender, or white flower heads, often grown in gardens.
2. Plant Biology any of various other composite plants, as the mistflower, having blue or white flowers.

• Greek agé̄raton, neuter of agé̄ratos unaging, equivalent. to a- a-⁶ + gērat- (stem of gêras) old age + -os adjective, adjectival suffix
• Neo-Latin; Latin agēraton
• 1560–70

Collins Concise English Dictionary © HarperCollins Publishers::

ageratum / ˌædʒəˈreɪtəm/ noun

1. any tropical American plant of the genus Ageratum, such as A. houstonianum and A. conyzoides, which have thick clusters of purplish-blue flowers

Etymology: 16th Century: New Latin, via Latin from Greek agēraton that which does not age, from a-¹ + gērat-, stem of gēras old age; the flowers of the plant remain vivid for a long time