| Osterrönfeld | Osterseen | Osterspai |
| Osterstedt | Osterwald | Osterwaldiella |
| Osterwaldiella monostricta | Osterwieck | Osterwitz |
| Osterwohle | Osterzell | Ostffyasszonyfa |
| Ostfriesische Lufttransport | Ostha | Ostha aega |
| Ostha aequata | Ostha basaliaria | Ostha basiflavata |
| Ostha cambogialis | Ostha centriponens | Ostha coryphata |
| Ostha costata | Ostha diplosticta | Ostha hypsea |
| Ostha hyriaria | Ostha irrespondens | Ostha maises |
| Ostha melanopasa | Ostha memoria | Ostha nomion |
| Ostha seleniata | Ostha sileniata | Osthausen-Wülfershausen |
| Ostheim | Ostheim, Haut-Rhin | Ostheldera |
| Ostheldera gracilis | Osthelderichola | Osthelderiella |
| Osthofen | Osthoffen | Ostholstein |
| Osthopis | Osthopis exocausta | Osthouse |
| Ostiano | Ostichthys japonicus | Ostiglia |
| Ostinato | Ostingersleben | Ostodes |
| Ostodes brazieri | Ostodes kuangii | Ostodes minor |
| Ostodes paniculata | Ostodes paniculata katharinae | Ostodes paniculata paniculata |
| Ostomalynus ovalis | Ostomopsis neotropicalis | Ostomopsis solitaria |
| Ostopovice | Ostorhinchus | Ostorhinchus aureus |
| Ostoros | Ostprignitz-Ruppin | Ostra |
| Ostra Vetere | Ostraciidae | Ostracion |
| Ostracion cubicus | Ostracion meleagris | Ostracion nasus |
| Ostracod | Ostracodermi | Ostracophyto aristalis |
| Ostracophyto flavicaudalis | Ostramondra | Ostrander, Minnesota |
| Ostrander, Ohio | Ostrata | Ostrau, Mittelsachsen |
| Ostrau, Saale | Ostrava | Ostrava (huyện) |
| Ostravice | Ostrá | Ostróda |
| Ostródzki | Ostrów Lubelski | Ostrów Mazowiecka |
| Ostrów Wielkopolski | Ostrea | Ostreidae |
| Ostren | Ostreville | Ostrhauderfehn |
| Ostricourt | Ostrinia | Ostrinia appositalis |
| Ostrinia dorsivittata | Ostrinia erythrialis | Ostrinia furnacalis |
| Ostrinia kasmirica | Ostrinia kurentzovi | Ostrinia latipennis |
| Ostrinia marginalis | Ostrinia narynensis | Ostrinia obumbratalis |
| Ostrinia orientalis | Ostrinia palustralis | Ostrinia penitalis |
| Ostrinia peregrinalis | Ostrinia putzufangensis | Ostrinia quadripunctalis |
| Ostrinia sanguinealis | Ostrinia scapulalis | Ostrinia zaguliaevi |
| Ostrinia zealis | Ostrinotes | Ostrožská Lhota |
| Ostrožská Nová Ves | Ostrołęcki | Ostrołęka |
| Ostrogoth | Ostrogoths | Ostrogozhsk |
| Ostrogozhsky (huyện) | Ostroh | Ostroh (huyện) |
| Ostrohe | Ostrolovský Újezd | Ostroměř |
| Ostroróg | Ostrov | Ostrov nad Oslavou |
| Ostrov u Bezdružic | Ostrov u Macochy | Ostrov, Ústí nad Orlicí |
| Ostrov, Benešov | Ostrov, Chrudim | Ostrov, Constanţa |
| Ostrov, Constanța | Ostrov, Havlíčkův Brod | Ostrov, Karlovy Vary |
| Ostrov, Příbram | Ostrov, Tulcea | Ostrovačice |
| Ostrovánky | Ostrovec | Ostrovec-Lhotka |
| Ostroveni | Ostrovnoy | Ostrovnoy, tỉnh Murmansk |
| Ostrovsky (huyện) | Ostrowiec Świętokrzyski | Ostrowiecki |
| Ostrowski | Ostrowskia magnifica | Ostružná |
| Ostružno | Ostrya carpinifolia | Ostrya chisosensis |
| Ostrya japonica | Ostrya knowltonii | Ostrya multinervis |
| Ostrya rehderiana | Ostrya trichocarpa | Ostrya virginiana |
| Ostrya yunnanensis | Ostryocarpus | Ostryocarpus riparius |
| Ostryocarpus zenkerianus | Ostryopsis davidiana | Ostryopsis nobilis |
| Ostrzeszów | Ostrzeszowski | Oststeinbek |
| Ostuacán | Ostvorpommern | Ostwald, Bas-Rhin |
| Ostwind | OSU | Osu! |
| Osugi Masato | Osumacinta | Osumi (quần đảo) |
| Osumilit | Osun-Osogbo | OSV-96 |
| Osvaldo Ardiles | Osvaldo Cruz | Osvaldo José Martins Júnior |
| Osvaldo Padilla | Osvětimany | Osvračín |
| Oswald Gracias | Oswald Spengler | Oswald Thomas Colman Gomis |
| Oswald Veblen | Oswaldia albifacies | Oswaldia anorbitalis |
| Oswaldia apicalis | Oswaldia assimilis | Oswaldia aurifrons |
| Oswaldia conica | Oswaldia eggeri | Oswaldia excitata |
| Oswaldia flavipalpis | Oswaldia flavitibia | Oswaldia gilva |
| Oswaldia glauca | Oswaldia hirsuta | Oswaldia immissa |
| Oswaldia intermedia | Oswaldia issikii | Oswaldia lauta |
| Oswaldia minor | Oswaldia muscaria | Oswaldia reducta |
| Oswaldia ruralis | Oswaldia sartura | Oswaldia solers |
| Oswaldia spectabilis | Oswaldia strigosa | Oswaldia valida |
| Oswaldia vesana | Oswaldo Cruz | Oswaldo de Oliveira |
| Oswayo, Pennsylvania | Oswayo, Quận Potter, Pennsylvania | Oswego, Illinois |
| Oswego, Kansas | Oswego, Quận Kendall, Illinois | Oswego, Quận Labette, Kansas |
| Osyka, Mississippi | Osyricera | Osyridicarpos schimperianus |
| Osyris alba | Osyris lanceolata | Osyris speciosa |
| Oszkó | Oszlár | Osztopán |
| Ota | Ota Kosuke | Ota Tetsuro |
| Ota Yoshiaki | Ota, Corse-du-Sud | Otağlı, Damal |
| Otaç, Hasköy | Otacanthus azureus | Otacanthus caparaoensis |
| Otacanthus platychilus | Otacanthus platychilus longifolius | Otacílio Costa |
| Otacı, Kızılcahamam | Otaces | Otaces lineata |
| Otachyrium | Otachyrium aquaticum | Otachyrium boliviense |
| Otachyrium grandiflorum | Otachyrium piligerum | Otachyrium pterigodium |
| Otachyrium seminudum | Otachyrium succisum | Otachyrium versicolor |
| Otacilia | Otacilia ambon | Otacilia armatissima |
| Otacilia komurai | Otacilia luna | Otacilia luzonica |
| Otacilia lynx | Otacilia mustela | Otacilia onoi |
| Otacilia ornata | Otacilia parva | Otacilia sinifera |
| Otacilia stella | Otacilia taiwanica | Otacilia vulpes |
| Otacilia zebra | Otagoa | Otagoa chathamensis |
| Otagoa nova | Otagoa wiltoni | Otake Naoto |
| Otaku | Otaku no Video | Otanche |
| Otani Hidekazu | Otani Ichiji | Otanthus |
| Otanthus maritimus | Otar Javashvili | Otaria |
| Otaria flavescens | Otariidae | Otaromia lugubris |
