cowtail noun3 •The tail of a cow.These burrs stuck to the tails of the cows as they walked by, and were brought to the cowpen, the cowtails greatly enlarged by the huge amount of cockleburs stuck on them. — 2002 •A stingray of species Pastinachus sephen. •A coarse wool of low quality, usually shorn from the hind legs of sheep. formscowtails