APLUS'TER, APLUS'TRE, noun [Latin from Gr. the summit of the poop of a ship.] An ensign, or ornament carried by ancient ships. It was shaped like a plume of feathers, fastened on the neck of a goose or swan, and to this was attached a party-colored ribbon, to indicate the course of the wind.
Source: Webster's 1828 American Dictionary ↗ · public-domain · returned verbatim, no AI