In Greek, Latin, and English, taurus means bull. Centaurus or centaur is of unknown origin, but is generally believed to have literally meant “bull slayer.” In Greek myth, horse-centaurs are simply called horse-centaurs. The “cen” part doesn’t mean horse at all.
How did “taur” come to mean something with a centauroid body plan in furry fandom, but centaur didn’t?