All articles starting with O

Otto Heckmann

Otto Heckmann (1901–1983) was a German astronomer who classified relativistic world models, led the Hamburg Observatory, and became the first Director General of the European Southern Observatory in 1962.

Ottó Herman

Ottó Herman (Herman Ottó; born Herrmann Károly Ottó; 1835–1914) was a self-taught Hungarian naturalist, ethnographer, archaeologist, and Independence Party member of Parliament often called the last great Hungarian polymath.

Otto Hofmann

Otto Hofmann (1896–1982), Austrian-born SS-Obergruppenführer, headed the SS Race and Settlement Main Office (RuSHA) 1940–1943, attended the Wannsee Conference, and was sentenced to 25 years at the 1948 RuSHA Trial, released in 1954.

Otto Hölder

Otto Hölder was a German mathematician (1859–1937) who held the chair at Leipzig and gave his name to Hölder's inequality, Hölder spaces, and the Jordan–Hölder theorem.

Otto Hönigschmid

Otto Hönigschmid was an Austrian-born chemist, the last classical atomic-weight analyst, who determined the atomic weights of nearly fifty elements and gave the first chemical proof of isotopes.

Otto II, Holy Roman Emperor

Otto II (955–983), Holy Roman Emperor from 973, son of Otto the Great; married the Byzantine kinswoman Theophanu, crushed Henry of Bavaria's revolts, suffered the Saracen defeat at Cap Colonne (982), and died of malaria in Rome leaving Otto III.

Otto III, Holy Roman Emperor

Otto III (980–1002), Ottonian Holy Roman Emperor, king from 983, son of Otto II and Theophano; pursued Renovatio imperii Romanorum from Rome, installed popes Gregory V and Sylvester II, founded Gniezno archbishopric, died aged 21 after Roman revolt.

Otto IV, Holy Roman Emperor

Otto IV, Holy Roman Emperor (c. 1175–1218), was the only Welf to hold the German kingship and imperial title, elected king in 1198 and crowned emperor in 1209.

Otto Kemp

Otto Kemp (Otto Severson Kemp, born 1999) is an American MLB infielder-outfielder for the Philadelphia Phillies; an undrafted free agent from Point Loma Nazarene University who debuted June 7, 2025.

Otto Kittel

Otto Kittel was a German Luftwaffe fighter ace of World War II, credited with 267 aerial victories on the Eastern Front before his death in 1945.

Otto Kratky

Otto Kratky (1902–1995) was an Austrian physical chemist who made small-angle X-ray scattering a general method for determining the size and shape of macromolecules in solution, and designed the Kratky camera.

Otto Krayer

Otto Krayer (1899–1982) was a German-American pharmacologist who led Harvard Medical School's pharmacology department from 1939 to 1966, known for cardiovascular work on the veratrum alkaloids.

Otto Künzli

Otto Künzli, born 1948 in Zürich, is a Swiss conceptual jeweler in Munich, best known for the 1980 bracelet Gold Macht Blind (Gold Makes You Blind).

Otto L. Lange

Otto L. Lange (Otto Ludwig Lange) was a German botanist and lichenologist, regarded as a founder of modern ecophysiology, who held the Chair of Botany II at Würzburg from 1967.

Otto L. Muskens

Otto L. Muskens is a Dutch nanophotonics researcher, Professor of Physics at the University of Southampton since 2014, known for light scattering in nanowire mats.

Otto Laporte

Otto Laporte (1902–1971) was a German-born American physicist at the University of Michigan, known for the Laporte rule in atomic spectroscopy and for shock tube research.

Otto Lara Resende

Otto Lara Resende (1922–1992) was a Brazilian writer and journalist from São João del-Rei, Minas Gerais, elected to the Academia Brasileira de Letras in 1979.

Otto Lehmann (physicist)

Otto Lehmann (1855–1922) was a German physicist who succeeded Heinrich Hertz at Karlsruhe, coined the term "liquid crystal," and promoted the field from 1889 onward.

Otto Lehmann-Russbüldt

Otto Lehmann-Russbüldt (1873–1964) was a German pacifist journalist who co-founded the Bund Neues Vaterland in 1914 and led its successor, the Deutsche Liga für Menschenrechte.

Otto Lilienthal

Otto Lilienthal was a German aviation pioneer who made the first sustained, repeatable human gliding flights between 1891 and 1896, and whose aerodynamic data guided the Wright brothers.

Otto Loewi

Otto Loewi was a German-born pharmacologist who proved in 1921, with two frog hearts, that nerves act by releasing chemicals, sharing the 1936 Nobel Prize with Henry Dale.

Otto Ludwig (writer)

Otto Ludwig was a German writer, dramatist, and critic born in Eisfeld in 1813 who died in Dresden in 1865 and is credited with coining the term poetic realism.

Otto Lummer

Otto Lummer (1860–1925) was a German experimental physicist whose precision blackbody measurements at the Physikalisch-Technische Reichsanstalt helped lead Max Planck to the quantum hypothesis in 1900.

Otto M. Hess

Otto M. Hess (1946–2011) was a Swiss cardiologist who headed the cardiovascular department at the University Hospital of Bern and led trials of homocysteine-lowering therapy after angioplasty.

Otto M. Nikodym

Otto M. Nikodym (Otton Marcin Nikodym, 1887–1974) was a Polish mathematician known for the Radon–Nikodym theorem, the Nikodym set, and the Nikodym–Grothendieck boundedness theorem; he taught at Kenyon College in Ohio from 1948 to 1965.

Oct 21, 2026

Otto Maier

Otto Maier (1887–1957), German coxswain of Ruderclub Frankfurt 1865; won gold in the coxed fours with outriggers for Ludwigshafener Ruderverein at the 1912 Stockholm Olympics, coxing all rounds; never won a German Championship.

Otto Maria Carpeaux

Otto Maria Carpeaux, born Otto Karpfen in Vienna in 1900, was an Austrian-born literary critic who fled to Brazil in 1939 and became a leading Brazilian literary critic.

Otto Mehls

Otto Mehls is a German pediatric nephrologist who built the study of childhood chronic kidney disease at Heidelberg University Children's Hospital from 1968 to 2004.

Otto Meyerhof

Otto Fritz Meyerhof was a German-born physician and biochemist who shared the 1922 Nobel Prize in Physiology or Medicine for discovering how oxygen consumption relates to lactic acid metabolism in muscle.