- One who is practical or hardheaded.
- Any of several weeds in or formerly classified in the genus Centaurea, particularly Russian knapweed (Acroptilon repens).
- Any of various freshwater cyprinid fishes of the genus Mylopharodon, or of saltwater sciaenid (Sciaenidae) fishes.
- (obsolete) Clash or collision of heads in contest.
- A brown diving duck, Aythya australis, native to Australia.
- (metallurgy) Residual ore that failed to melt during a smelting process.