English English Wikipedia has an article on:social insurance numberWikipedia Noun social insurance number (plural social insurance numbers) (Canada) A nine-digit number issued by the government of Canada to citizens, permanent residents, and some categories of temporary residents, for official identification in the provision of government services and income taxation. Abbreviation: SIN. Translations Translations French: numéro d’assurance sociale f, (abbreviation) NAS (fr) f See also social security number (US)Wikiwand - on Seamless Wikipedia browsing. On steroids.