sumpter

Từ điển American Heritage Dictionary 4th

sump·ter (sŭmpʹtər)n.
A pack animal, such as a horse or mule. [Middle English, driver of a packhorse, from Old French sometier, from Vulgar Latin *saumatārius, from Late Latin sagma, sagmat-, packsaddle, from Greek, from sattein, to pack.]