One of a group of polycyclic, 17-carbon-atom, fused-ring compounds occurring both in natural and synthetic forms. Included here are naturally occurring and synthetic steroids, bufanolides, cardanolides, homosteroids, norsteroids, and secosteroids.
(Slot-Cardinality Steroid _Fused-Ring 1)
(Slot-Cardinality Steroid _Polycyclic 1)
(=> (Steroid ?Self)
(Exists (?A) (And (Prime-Component ?Self ?A) (Carbon-17 ?A))))