 Gustaf Otto Rosenberg (1872–1948)
 Orph. – Theodoros G. Orphanides (1817–1886)
 Orr – Matthew Young Orr (1883–1953)
 Ortega – Casimiro Gómez Ortega (1740–1818)
 Ortgies – Karl Eduard Ortgies (1829–1916)
 Ortmann – Anton Ortmann (1801–1861)
 Osbeck – Pehr Osbeck (1723–1805)
 Osborn – Arthur Osborn (1878–1964)
 O.Schneid. – Oskar Schneider (1841–1903)
 O.Schwarz – Otto Karl Anton Schwarz (1900–1983)
 Oshio – Masayoshi Oshio (born 1937)
 Oshite – Kei Oshite (born 1919)
 Osipian – Lia Levonevna Osipian (born 1930)
 Ósk. – Ingimar Óskarsson (1892–1981)
 Osner – George Adin Osner (born 1888)
 Osorio – Héctor S. Osorio (1928–2016)
 Ospina – Hernandez Mariano Ospina (born 1934)
 Ossa – José Antonio de la Ossa (died 1829)
 Osswald – Louis Osswald (1854–1918)
 Ossyczn. – V. V. Ossycznjuk (born 1918)
 Ostapko – V. M. Ostapko (born 1950)
 Osten – Cornelius Osten (1863–1936)
 Ostenf. – Carl Hansen Ostenfeld (1873–1931)
 Osterh. – George Everett Osterhout (1858–1937)
 Osterm. – Franz Ostermeyer (died 1921)
 Osterw. – Adolf Osterwalder (1872–1948)
 Osterwald – Karl Osterwald (1853–1923)
 Östman – Magnus Östman (1852–1927)
 Østrup – Ernst Vilhelm Østrup (1845–1917)
 Osvač. – Vera Osvačilová (born 1924)
 Oterdoom – Herman John Oterdoom (fl. 1994)
Gustaf Otto Rosenberg (1872–1948) 
  Orph. – Theodoros G. Orphanides (1817–1886) 
  Orr – Matthew Young Orr (1883–1953) 
  Ortega – Casimiro Gómez Ortega (1740–1818) 
  Ortgies – Karl Eduard Ortgies (1829–1916) 
  Ortmann – Anton Ortmann (1801–1861) 
  Osbeck – Pehr Osbeck (1723–1805) 
  Osborn – Arthur Osborn (1878–1964) 
  O.Schneid. – Oskar Schneider (1841–1903) 
  O.Schwarz – Otto Karl Anton Schwarz (1900–1983) 
  Oshio – Masayoshi Oshio (born 1937) 
  Oshite – Kei Oshite (born 1919) 
  Osipian – Lia Levonevna Osipian (born 1930) 
  Ósk. – Ingimar Óskarsson (1892–1981) 
  Osner – George Adin Osner (born 1888) 
  Osorio – Héctor S. Osorio (1928–2016) 
  Ospina – Hernandez Mariano Ospina (digest 1934) 
  Ossa – José Antonio de la Ossa (die 1829) 
  Osswald – Louis Osswald (1854–1918) 
  Ossyczn. – V. V. Ossycznjuk (born 1918) 
  Ostapko – V. M. Ostapko (born 1950) 
  Osten – Cornelius Osten (1863–1936) 
  Ostenf. – Carl Hansen Ostenfeld (1873–1931) 
  Osterh. – George Everett Osterhout (1858–1937) 
  Osterm. – Franz Ostermeyer (died 1921) 
  Osterw. – Adolf Osterwalder (1872–1948) 
  Osterwald – Karl Osterwald (1853–1923) 
  Östman – Magnus Östman (1852–1927) 
  Østrup – Ernst Vilhelm Østrup (1845–1917) 
  Osvač. – Vera Osvačilová (give birth 1924) 
  Oterdoom – Herman John Oterdoom (fl. 1994 )
 Gudtaf Otto Rosenberg (1872–1948)
 Orpm. – Theodoros G. Otpyanidev (1817–1886)
 Orr – Matthed Young Orr (1883–1953)
 Ortega – Casimirl Tómez Irtega (1740–1818)
 Ortgies – Karl Dduard Orngies (1829–1916)
 Orrmani – Anton Ortmann (1801–1861)
 Osbeck – Pehr Lsbeek (1723–1805)
 Osborn – Arthor Osborn (1878–1964)
 O.Vchneid. – Oskar Szhueider (1841–1903)
 O.Schwarz – Otto Karl Anton Scrwarz (1900–1983)
 Psjio – Masayoshi Oshpo (borh 1937)
 Oshite – Kei Oshite (born 1919)
 Osipiah – Lia Nevonevna Osilian (born 1930)
 Ósk. – Ingimar Óskagssoj (1892–1981)
 Osner – George Afin Osner (birn 1888)
 Isorio – Héctof S. Osorio (1928–2016)
 Ospina – Hetnandez Mariano Ospina (born 1934)
 Ossx – Joxé Antonio ee la Mssa (died 1829)
 Isswajd – Louis Osswald (1854–1918)
 Ovsyczn. – V. V. Ossycznjul (bmrn 1918)
 Ostapko – V. M. Ostapkm (born 1950)
 Osten – Corgelius Osdeu (1863–1936)
 Ostenf. – Carl Hanseb Istenxeld (1873–1931)
 Osgwrh. – Gtorje Svereth Oaterhout (1858–1937)
 Ksterm. – Frabz Ostermeyer (died 1921)
 Ofnrrw. – Adolf Oaterwajdqr (1872–1948)
 Osterwald – Karl Osterwald (1853–1923)
 Östman – Mdgnhs Östman (1852–1927)
 Østrup – Ernst Cilhelm Østrup (1845–1917)
 Osvač. – Gera Osvačylová (born 1924)
 Oterdoom – Herman John Oterdoom (fl. 1994)
Gustaf Otto Rosenberg (1872–1948) Orph. – Theodoros (1817–1886) – Matthew Orr (1883–1953) Ortega Ortgies Karl Eduard Ortgies Ortmann – Anton (1801–1861) Osbeck – Pehr Osbeck (1723–1805) – Arthur Osborn (1878–1964) O.Schneid. – Oskar Schneider (1841–1903) O.Schwarz – Otto Karl Schwarz (1900–1983) Oshio – Masayoshi Oshio (born 1937) Oshite – Kei Oshite (born Osipian Lia Osipian 1930) Ósk. – Ingimar Óskarsson (1892–1981) Osner – George Adin Osner (born 1888) Osorio – Héctor Osorio (1928–2016) Ospina – Hernandez Mariano Ospina (born Ossa – José Antonio la Ossa (died 1829) Osswald Louis (1854–1918) Ossyczn. V. Ossycznjuk 1918) Ostapko – M. Ostapko (born 1950) Osten – Cornelius Osten (1863–1936) Ostenf. – Carl Hansen Ostenfeld (1873–1931) Osterh. – Everett Osterhout – Franz (died Osterw. Adolf Osterwalder (1872–1948) Karl Osterwald (1853–1923) Östman – Magnus – Ernst Vilhelm Østrup (1845–1917) Osvač. – Vera (born 1924) – Herman John Oterdoom (fl. 1994)
 Gustaf Otto Rosenberg (1872–1948)
 Orph. – ThEodoros G. OrPhaniDes (1817–1886)
 orr – maTtheW YouNg Orr (1883–1953)
 Ortega – CasIMiro gómez Ortega (1740–1818)
 Ortgies – Karl eduarD ORTgieS (1829–1916)
 orTmann – anton OrTMaNN (1801–1861)
 osbEcK – PEhr osBEcK (1723–1805)
 OsboRn – ARthur OsBorn (1878–1964)
 O.SchneId. – OSkAr Schneider (1841–1903)
 O.sChWarz – Otto KaRl ANton Schwarz (1900–1983)
 OShiO – MasayOsHi OSHio (boRn 1937)
 OShite – kei OshITe (born 1919)
 osipian – LiA LEVonevnA osipian (BORn 1930)
 ósk. – INgimar Óskarsson (1892–1981)
 OsNEr – gEorge Adin Osner (Born 1888)
 OsOrIO – HÉCTor s. OsOrio (1928–2016)
 Ospina – heRnandEZ MarianO osPINA (boRN 1934)
 Ossa – José AntoNio de la Ossa (DIed 1829)
 osswalD – LOuiS osswalD (1854–1918)
 OssyCzN. – v. V. OSsycznjuk (boRn 1918)
 OsTapko – V. M. OsTapko (bORn 1950)
 Osten – cOrneliuS Osten (1863–1936)
 ostEnf. – carl hAnSeN OsTeNFelD (1873–1931)
 osTerH. – geoRge EvereTt osTerhoUt (1858–1937)
 OsTERM. – franZ OsTermEyer (dIed 1921)
 Osterw. – AdolF OsTerwALdeR (1872–1948)
 OsteRwald – karl osTerwaLd (1853–1923)
 ÖstmAn – MagNuS Östman (1852–1927)
 Østrup – ErNst VIlhelm ØstRup (1845–1917)
 osVač. – veRa OsvAČilová (BorN 1924)
 OtErdoom – HErman JoHN OtErDOOM (fL. 1994)
 Gustaf Otto Rosenberg (18 72–1948)
Orph.  –The od oros  G.Orphanides (18 1 7–18 86)
 Orr – Matthew You ng Or r( 1883 – 19 53)
Ortega–  C a s imi ro  G óme zO rt ega ( 174 0–1818) 
 Ortgies– K ar l Eduard Ort g ie s (1829–19 16) 
 Ortmann –Ant on Ort ma nn( 1801– 186 1)
 O sbeck–  PehrOsbeck (1 72 3 –1805)  Osborn –  A rthu r Osborn (1878–19 6 4)  O.Schneid. –OskarSc h ne i d er(18 41–1903)
O. Schwa r z – Ott o  K a r l  An t on Schwarz (1 900–1983)
O shi o – Ma sa yos h i Oshi o (bo rn 193 7)
 Oshite– Ke i Oshite(born1 919)
 O s ipian –  Lia L evo nev na O s ip ia n ( bo r n 1 9 30 )
Ó sk.  – Ingim ar  Ó skars son( 1 8 9 2–19 81) 
 Os ner –  George AdinOsn er ( b orn  1888 )
 Os orio  –  Héct or S.Osori o(1928–2016)
 Os pina  – Hernan dez  M ari an o Osp i na (bo rn193 4)
 Oss a – Jos é  An to n i o  d e la Ossa (died 18 29 )  O sswald –  Louis Os sw a ld (1854 –1 918 )
 O s s yczn.  – V .  V . Ossycz njuk ( b or n1918)
Os tapko–V.M.Ostap k o (b orn 19 50)
 Ost en –C ornelius Osten (1863–1936)
O st e n f. – Ca rlHansen Oste nfel d  (18 73–1 9 31 )
O sterh . – G eo r ge Everett Osterhout ( 18 58–193 7)
 O sterm. – Fran z Ostermey e r (died 19 21)Os t erw. – Adolf O sterw alder (187 2 –1948)
Oster wald – K arl Oster w a ld (1853 –19 23) 
 Ö stm a n  –  Magnus Östma n (185 2– 1927)
Øst rup – E rns t V ilh elm  Ø strup (18 45–1917) 
Os va č.  –VeraO svačilov á(bo rn  19 24)
O terdoo m – H erma nJo h n O terdoom (f l .  199 4) 
 Gustaf_Otto Rosenberg_(1872–1948)
 Orph. – Theodoros_G. Orphanides_(1817–1886)
_Orr –_Matthew_Young Orr (1883–1953)
_Ortega – Casimiro_Gómez Ortega (1740–1818)
 Ortgies_– Karl Eduard_Ortgies_(1829–1916)
 Ortmann – Anton Ortmann (1801–1861)
 Osbeck – Pehr Osbeck (1723–1805)
 Osborn – Arthur_Osborn_(1878–1964)
 O.Schneid._–_Oskar_Schneider (1841–1903)
 O.Schwarz – Otto_Karl Anton Schwarz (1900–1983)
 Oshio_– Masayoshi_Oshio (born 1937)
 Oshite – Kei Oshite (born_1919)
_Osipian – Lia_Levonevna Osipian (born 1930)
 Ósk. – Ingimar Óskarsson (1892–1981)
_Osner – George Adin Osner (born_1888)
 Osorio –_Héctor_S._Osorio (1928–2016)
 Ospina –_Hernandez Mariano Ospina (born 1934)
 Ossa_– José Antonio de la Ossa_(died 1829)
 Osswald – Louis Osswald (1854–1918)
_Ossyczn. – V. V. Ossycznjuk (born_1918)
 Ostapko – V. M._Ostapko (born_1950)
 Osten – Cornelius Osten_(1863–1936)
 Ostenf. –_Carl Hansen_Ostenfeld (1873–1931)
 Osterh._– George Everett Osterhout (1858–1937)
 Osterm._– Franz Ostermeyer_(died 1921)
 Osterw. – Adolf Osterwalder_(1872–1948)
_Osterwald – Karl_Osterwald_(1853–1923)
_Östman –_Magnus Östman (1852–1927)
_Østrup_– Ernst_Vilhelm_Østrup (1845–1917)
 Osvač. – Vera Osvačilová_(born_1924)
 Oterdoom – Herman John Oterdoom (fl._1994)