Definition that contains atop
- tier one of two or more layers one atop another
- triceratops huge ceratopsian dinosaur having three horns and the neck heavily armored with a very solid frill
- frill (paleontology) a bony plate that curves upward behind the skull of many ceratopsian dinosaurs
- velociraptor small active carnivore that probably fed on protoceratops; possibly related more closely to birds than to other dinosaurs
- keratoconus abnormal cone-shaped protrusion of the cornea of the eye; can be treated by epikeratophakia
- calochortus kennedyi mariposa with clusters of bell-shaped vermilion or orange or yellow flowers atop short stems; southern California to Arizona and Mexico
- atopic dermatitis a severe form of dermatitis characterized by atopy
- ranunculales herbs, shrubs and trees: includes families Ranunculaceae; Annonaceae; Berberidaceae; Magnoliaceae; Menispermaceae; Myristicaceae; Nymphaeaceae; Lardizabalaceae; Lauraceae; Calycanthaceae; Ceratophyllaceae; Cercidiphyllaceae
- marginocephalian includes boneheaded (pachycephalosaurs) and horned (ceratopsian) dinosaurs
- elegant brodiaea brodiaea having an umbel of violet or blue-violet flowers atop a leafless stalk; northern Oregon to southern California