sau·rop·si·da \-psədə\noun plural Usage: capitalized Etymology: New Latin, from saur- + Greek opsis appearance + New Latin -ida — more at optic in some especially former classifications: a group of vertebrates comprising the reptiles and birds — compare ichthyopsida, mammalia • sau·rop·si·dan\(ˈ) ̷ ̷| ̷ ̷sədən\adjective or noun • sau·rop·sid·i·an\| ̷ ̷ˌ ̷ ̷|sidēən\adjective