of force, Newton's law of cooling, Newton's law of gravitation, Newton's laws of motion, Newton's rings, Newtonian reflecting telescope. Nicarao, Nahua ruler – Nicaragua. William Nicol, Scottish geologist and physicist - Nicol prism. Jean Nicot, French explorer – nicotine. Arthur Nielsen, American market analyst – Nielsen ratings, Nielsen Media Research. Florence Nightingale, British nurse – Nightingale Pledge, Florence Nightingale effect. Niobe, Greek-Roman mythological character – niobium. Aron Nimzowitsch, Latvian-Russian-Danish chessplayer – Nimzo–Indian Defence. Peter Norman Nissen, Canadian-American-British engineer – Nissen hut. Richard Nixon, American president – Nixonomics, Nixon mask. Alfred Nobel, Swedish inventor and activist – Nobel Prizes, nobelium. Emmy Noether, German mathematician – Noether's theorem, Noetherian rings. Norbert of Xanten, German bishop – The Norbertines. Ian Norman and Gerry Harvey, Australian businessmen – Harvey Norman. Edward Lawry Norton, American engineer – Norton's theorem. Peter Norton, American businessman – Norton AntiVirus. Pedro Nunes, Portuguese mathematician and inventor – nonius O Barack Obama, American President – Obamacare, Obamanomics. Obsius, discoverer (in Pliny) of an obsidian-like stone – obsidian. Oceanus, Greek-Roman mythological character – ocean. Robert Ochsenfeld and Walter Meissner, German physicists – Meissner–Ochsenfeld effect (Meissner effect). William of Ockham, British philosopher – Occam's Razor. Odysseus, Greek mythological character – odyssey. Oedipus, Greek mythological character – Oedipus complex. Oengus I of the Picts, Pictian king – Angus. Georg Ohm, German physicist – ohm, Ohm's law, Ohm's acoustic law. Nobuo Okishio, Japanese economist – Okishio's theorem Onan, Biblical character – onanism. Eugene Onegin, Russian literary character – Onegin stanza. John Joseph O'Neill, American journalist - O'Neill's bridge (a so-called artificial bridge on the moon's surface, between Promontorium Lavinium and Promontorium Olivium at the western part of Mare Crisium's rim). Jan Oort, Dutch astronomer – Oort cloud. Adam Opel, German businessman – Opel. Daphne Oram, British composer and electronic musician - Oramics. William of Orange, Dutch politician – Orangism. Leonard Ornstein, Dutch physicist – Ornstein–Zernike equation, Ornstein–Uhlenbeck process. Orpheus, Greek mythological character – orphism (religion), orphism (art), Orphean warbler. Charles Boyle, 4th Earl of Orrery, British nobleman – the orrery. Hans Christian Ørsted, Danish physicist and chemist – oersted, unit of magnetic field strength. George Orwell, British novelist – Orwellian. Robert Bayley Osgood, American physician and Carl B. Schlatter, Swiss physician – Osgood–Schlatter disease. Osman I, Turkish sultan – Ottoman Empire. Wilhelm Ostwald, Latvian-German chemist – Ostwald process. Nicolaus Otto, German engineer and inventor – Otto engine. John Owen, British chess player – Owen's