smallmouth black bass noun alsosmallmouthed black bassorsmallmouth bassorsmallmouthed bass\ˈ ̷ ̷ˌ ̷ ̷-\; orsmallmouth\ˈ ̷ ̷ˌ ̷ ̷\ : a black bass (Micropterus dolomieu) that lives chiefly in cool clear rivers and lakes, is bronzy green above and lighter below, and has the angle of the jaw falling below the eye — compare largemouth black bass [smallmouth bass]