The Collaborative International Dictionary
vitamin B
vitamin B \vitamin B\ n. a group of water-soluble vitamins originally thought to be a single vitamin but now separated into several B vitamins.
Syn: B-complex vitamin, B complex, vitamin B complex, B vitamin.
Wiktionary
vitamin b
n. (context vitamin English) Any member of the vitamin B complex.
WordNet
vitamin B
n. originally thought to be a single vitamin but now separated into several B vitamins [syn: B-complex vitamin, B complex, vitamin B complex, B vitamin, B]