welterweightPronunciation: /ˈwɛltəweɪt/Translate welterweight | into French | into Italian Definition of welterweight noun [mass noun] a weight in boxing and other sports intermediate between lightweight and middleweight. In the amateur boxing scale it ranges from 63.5-67 kg. [count noun] a welterweight boxer or other competitor. Origin: early 19th century: welter of unknown originwelterweight in other Oxford dictionaries Definition of welterweight in the US English dictionary