単たん弓きゅう綱こうMeanings1nounSynapsidaScientific term for a class of amniotes that includes mammals and their extinct relatives. Used in paleontology and biology.単たん弓きゅう綱こうは哺ほ乳にゅう類るいを含ふくむ脊せき椎つい動どう物ぶつの一いち群ぐんである。Synapsida is a group of vertebrates that includes mammals.