Adjective Satellite
of a chemical compound having a ring with four members
Source: WordNetThe image shows that the thiazolidine ring and fused four-membered β-lactam are not in the same plane The term " penam " is used to describe the common core skeleton of a member of the penicillins. Source: Internet
The C 62 has the structure in which a four-membered ring is surrounded by four six-membered rings. Source: Internet