The Collaborative International Dictionary of English v.0.48:
Blow \Blow\, n. [OE. blaw, blowe; cf. OHG. bliuwan, pliuwan, to
beat, G. bl[aum]uen, Goth. bliggwan.]
1. A forcible stroke with the hand, fist, or some instrument,
as a rod, a club, an ax, or a sword.
Well struck ! there was blow for blow. --Shak.
2. A sudden or forcible act or effort; an assault.
A vigorous blow might win [Hanno's camp]. --T.
3. The infliction of evil; a sudden calamity; something which
produces mental, physical, or financial suffering or loss
(esp. when sudden); a buffet.
A most poor man, made tame to fortune's blows.
At a blow, suddenly; at one effort; by a single vigorous
act. "They lose a province at a blow." --Dryden.
To come to blows, to engage in combat; to fight; -- said of
individuals, armies, and nations.
Syn: Stroke; knock; shock; misfortune.