Gonane (cyclopentanoperhydrophenanthrene) is a chemical compound with formula C17H28, whose structure consists of four hydrocarbon rings fused together: three cyclohexane units and one cyclopentane.

[1] There are many forms of gonane, but only a few occur naturally in living organisms.

Estrane, androstane, and pregnane are derivatives of gonane with additional methyl or ethyl groups attached to certain carbon positions.

The term gonane is also used to describe a group of progestins that are similar to levonorgestrel but have a slightly different structure than other hormones like estranes.

The term gonane is also used to refer to a group of progestins[2] that are carbon 18-homologated 19-nortestosterone derivatives including levonorgestrel and its analogues.