老表 is a colloquial term from southern China, especially common in Jiangxi, Hunan, and Guangdong. It literally means 'old cousin' (maternal side or paternal aunt's side), but in everyday use it's a friendly way to address a male stranger — like 'buddy' or 'pal' in English. The term carries a warm, informal, and regional flavor; you'd use it with someone around your age or younger, not in formal settings.