a type of bet whereby the better guesses whether a given statistic, usually the combined score of a sports match, will be higher or lower than a bookmaker's prediction
2.
a two-barrelled firearm with one barrel on top of the other
adjective
3.
(of a two-barrelled firearm) having one barrel on top of the other
over-under in American English
(ˈoʊvərˈʌndər)
US
adjective
designating a double-barreled firearm with one barrel over the other