ballista

ballista [bə'lɪstə]  [bə'lɪstə] 

ballista 基本解释
弩炮;抛石机,投石器;
ballista 英英释义

noun

1. ballista

1. an engine that provided medieval artillery used during sieges
    a heavy war engine for hurling large stones and other missiles

    Synonym: catapult arbalest arbalist bricole mangonel onager trebuchet trebucket