The Collaborative International Dictionary
vitamin B complex
vitamin B complex \vitamin B complex\ n. a mixture of water-soluble vitamins originally thought to be a single vitamin but now known to be a mixture of several compounds with vitaminic activity.
Syn: B complex, vitamin B complex, vitamin B, B vitamin.
Wiktionary
vitamin b complex
n. A group of water-soluble vitamins, once thought to be a single vitamin, occurring in yeast, liver, eggs etc.
WordNet
vitamin B complex
n. originally thought to be a single vitamin but now separated into several B vitamins [syn: B-complex vitamin, B complex, vitamin B, B vitamin, B]