The Collaborative International Dictionary of English v.0.48:
wager \wa"ger\ (w[=a]"j[~e]r), n. [OE. wager, wajour, OF.
wagiere, or wageure, F. gageure. See Wage, v. t.]
1. Something deposited, laid, or hazarded on the event of a
contest or an unsettled question; a bet; a stake; a
Besides these plates for horse races, the wagers may
be as the persons please. --Sir W.
If any atheist can stake his soul for a wager
against such an inexhaustible disproportion, let him
never hereafter accuse others of credulity.
2. (Law) A contract by which two parties or more agree that a
certain sum of money, or other thing, shall be paid or
delivered to one of them, on the happening or not
happening of an uncertain event. --Bouvier.
Note: At common law a wager is considered as a legal contract
which the courts must enforce unless it be on a subject
contrary to public policy, or immoral, or tending to
the detriment of the public, or affecting the interest,
feelings, or character of a third person. In many of
the United States an action can not be sustained upon
any wager or bet. --Chitty. --Bouvier.
3. That on which bets are laid; the subject of a bet.
Wager of battel, or Wager of battle (O. Eng. Law), the
giving of gage, or pledge, for trying a cause by single
combat, formerly allowed in military, criminal, and civil
causes. In writs of right, where the trial was by
champions, the tenant produced his champion, who, by
throwing down his glove as a gage, thus waged, or
stipulated, battle with the champion of the demandant,
who, by taking up the glove, accepted the challenge. The
wager of battel, which has been long in disuse, was
abolished in England in 1819, by a statute passed in
consequence of a defendant's having waged his battle in a
case which arose about that period. See Battel.
Wager of law (Law), the giving of gage, or sureties, by a
defendant in an action of debt, that at a certain day
assigned he would take a law, or oath, in open court, that
he did not owe the debt, and at the same time bring with
him eleven neighbors (called compurgators), who should
avow upon their oaths that they believed in their
consciences that he spoke the truth.
Wager policy. (Insurance Law) See under Policy.
Wagering contract or gambling contract. A contract which
is of the nature of wager. Contracts of this nature
include various common forms of valid commercial
contracts, as contracts of insurance, contracts dealing in
futures, options, etc. Other wagering contracts and bets
are now generally made illegal by statute against betting
and gambling, and wagering has in many cases been made a
criminal offence. [Webster 1913 Suppl.]