Adrastea

prefix meaning "not, without," from Greek a-, an- "not" (the "alpha privative"), from PIE root *ne- "not" (source also of English un-).

In words from Greek, such as abysmal, adamant, amethyst; also partly nativized as a prefix of negation (asexual, amoral, agnostic). The ancient alpha privatum, denoting want or absence.

Greek also had an alpha copulativum, a- or ha-, expressing union or likeness, which is the a- expressing "together" in acolyte, acoustic, Adelphi, etc. It is from PIE root *sem- (1) "one; as one, together with."

"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).