B-complex vitamin and Water-soluble vitamin

B-complex vitamin noun - Originally thought to be a single vitamin but now separated into several B vitamins.

Water-soluble vitamin and B-complex vitamin are semantically related. In some cases you can use "Water-soluble vitamin" instead a noun phrase "B-complex vitamin".

Water-soluble vitamin noun - Any vitamin that is soluble in water.

B-complex vitamin and water-soluble vitamin are semantically related. Sometimes you can replace phrase "B-complex vitamin" with "Water-soluble vitamin", this phrases are similar.