cyclic hydrocarbon
Technical term in organic chemistry for a hydrocarbon whose carbon atoms form a ring structure.
Benzene is a typical cyclic hydrocarbon.
鎖式炭化水素 refers to open-chain (acyclic) hydrocarbons, in contrast to the ring structure of 環式炭化水素.
Compound of 環式 (cyclic) + 炭化水素 (hydrocarbon). The exact historical derivation is uncertain; the spelling is conventionally associated with the chemical meaning.