Sterol and Steroid

Sterol noun - Any of a group of natural steroid alcohols derived from plants or animals; they are waxy insoluble substances.

Steroid and sterol are semantically related. In some cases you can use "Steroid" instead a noun "Sterol".

Steroid noun - Any of several fat-soluble organic compounds having as a basis 17 carbon atoms in four rings; many have important physiological effects.

Sterol and steroid are semantically related. Sometimes you can replace term "Sterol" with "Steroid", this nouns are similar.