A very large group of secondary metabolites, including monoterpenes (with 10 carbons), sesquiterpenes (15 C), diterpenes (20 C), triterpenes (30 C), steroids (27 or less), tetraterpenes (40 C).
All steroids belong to the class of compounds known as terpenoids. All of these compounds have in common the same two C5H8 isoprene precursors employed for their synthesis, namely, isopentenyl pyrophosphate and dimethylallyl pyrophosphate.