dromedary (n.)

"thoroughbred Arabian camel," late 13c., from Old French dromedaire and directly from Late Latin dromedarius "kind of camel," from Latin dromas (genitive dromados), from Greek dromas kamelos "running camel," from dromos "a race course," from dramein "to run," from PIE *drem- "to run" (source also of Sanskrit dramati "runs, goes," perhaps also Old English trem "footstep").

A variety of the one-humped Arabian camel bred and trained for use as a saddle-animal, "and comparing with the heavier and slower varieties as a race-horse does with a cart-horse; it is not a different animal zoologically speaking" [Century Dictionary]. An early variant in English was drumbledairy (1560s).