pickback number . back number {n.} Something out of fashion, or out of date. Among today's young people a waltz like "The Blue Danube" is a hack number. Categories: add yours noun Source: A Dictionary of American Idioms 'back number' on video back number - 水平線 back number - エメラルド (TBS系 日曜劇場『危険なビーナス』主題歌) back number - 「瞬き」Music Video back number – HAPPY BIRTHDAY<NO MAGIC TOUR 2019 at大阪城ホール>期間限定公開 sort: relevance, mode: exact match, q: "back number", maxResults: 4, videoEmbeddable: true, videoSyndicated: true, safeSearch: strict, type: video Subscribe to: American IdiomsEnglish Slang Add my comment