n.
Pronunciation: ˌ a-j ə - ' r ā -t ə m
Function: noun
Inflected Form: plural -tum also -tums
Etymology: New Latin, genus name, from Greek ag ē ratos ageless, from a- + g ē ras old age ― more at GERONT-
Date: 1866
: any of a genus ( Ageratum ) of annual tropical American composite herbs often cultivated for their small showy heads of usually blue or white flowers also : a related blue-flowered perennial ( Eupatorium coelestinum )