B12 Full Form. Full Meaning of B12 Find long form and abbreviation, slang or definition of B12. What does B12 mean? What does B12 stand for? We are providing world largest and most comprehensive acronyms, names, abbreviations database directory on the Internet. Our data base contains more than 8,00,000 terms abbreviations and acronyms. You can also search unique terms more than 4,00,000 general Comprehensive words.