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1. (Gambling, except Cards) gambling a type of bet whereby the better guesses whether a given statistic, usually the combined score of sport match, will be higher or lower than a bookmaker's prediction
2. (Firearms, Gunnery, Ordnance & Artillery) a two-barrelled firearm with one barrel on top of the other
(Firearms, Gunnery, Ordnance & Artillery) (of a two-barrelled firearm) having one barrel on top of the other