Volcano
Photographs by Peter Elliston »

YouTube
YouTube. Video hosting service, User- generated content, History of YouTube, Chad Hurley, Steve Chen (YouTube), Jawed Karim, Social impact of YouTube, Critic... »

Aardonyx
Genus, Dinosaur, Prosauropoda, Early Jurassic, Sauropoda, Apatosaurus, Paleontology, Proceedings of the Royal Society, Natural History Museum, Cladistics »

Abrasive
Mineral, Polishing, Polishing (metalworking), Cutting, Drilling, Sharpening, Lapping, Sandpaper, Abrasive machining, File (tool), Abrasion (medical), Excoria... »

Addition
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Adoption
From Hell to Heaven »

Albacore
Tuna, Scombridae, Bonito, Kilogram, Fishery, Angling, Longline fishing, Troll (angling), Seine fishing, Recreational fishing, Fish anatomy, Dorsal fin, Mercu... »

Almagest
Latin, Arabic language, English language, Mathematics, Astronomy, Star, Planet, Greek language, Ptolemy, Geocentric model, Islamic Golden Age, Europe, Middle... »

Amchitka
Plate tectonics, Rat Islands, Aleutian Islands, Oceanic climate, Aleut, Alaska Purchase, World War II, Aleutian Islands Campaign »

Ammolite
Opal, Gemstone, Rocky Mountains, Chrysoberyl, Fossil, Ammonite, Mineral, Nacre, Biogenic substance, Amber, CIBJO, Alberta, Lethbridge, Korite International »