any Eurasian plant of the genus Centaurium, esp C. erythraea, having purplish-pink flowers and formerly believed to have medicinal properties: family Gentianaceae
2.
any plant of the genus Centaurea, which includes the cornflower and knapweed: family Compositae (composites)
Word origin
C14: ultimately from Greek Kentauros the Centaur; from the legend that Chiron the Centaur divulged its healing properties