pickso long . so long {interj.}, {informal} Good-bye. — Used when you are leaving someone or he is leaving you. So long, I will be back tomorrow. Categories: add yours informal interjection Source: A Dictionary of American Idioms 'so long' on video Malfa - So Long (ASPARAGUSproject Remix) Video VDJ Puzzle So Long Killval - So Long (Official Music Video) Malfa - So Long (M.a.o.s. Beats Remix) 1 Hour Music sort: relevance, mode: exact match, q: "so long", maxResults: 4, videoEmbeddable: true, videoSyndicated: true, safeSearch: strict, type: video Subscribe to: American IdiomsEnglish Slang Post my comment