ornithischia: extinct terrestrial reptiles having bird-like pelvises: armored dinosaurs (thyreophorans); boneheaded and horned dinosaurs (marginocephalians); duck-billed dinosaurs (euronithopods)
biological group: a group of plants or animals
sidelight: light carried by a boat that indicates the boat's direction; vessels at night carry a red light on the port bow and a green light on the starboard bow