dromedary (n.)
late 13c., from Old French dromedaire, from Late Latin dromedarius "kind of camel," from Latin dromas (genitive dromados), from Greek dromas kamelos "running camel," from dromos "a race course," from PIE *drem-, from possible base *der- "to run, walk, step" (cognates: Sanskrit dramati "runs, goes," Greek dromas "running," Middle High German tremen "to rock, shake, sway"). One-humped Arabian camels were bred and trained for riding. An early variant was drumbledairy (1560s).