O.E. hleapan "to jump, run, leap" (class VII strong verb; past tense hleop, pp. hleapen), from P.Gmc. *khlaupan (cf. O.S. hlopan, O.N. hlaupa, O.Fris. hlapa, Du. lopen, Ger. laufen "to run," Goth. us-hlaupan "to jump up"), of uncertain origin, with no known cognates beyond Germanic. The noun is O.E. hlyp (Anglian *hlep). Leap-frog, the children's game, is attested from 1590s.
Rapidly, or in fast progress, as in The corn is growing by leaps and bounds, or School enrollment is increasing by leaps and bounds. This term is a redundancy, since leap and bound both mean “spring” or “jump,” but the two words have been paired since Shakespeare's time and are still so used.