| OST | extinct fishlike jawless vertebrate having a heavily armored body |
|---|---|
| OST | extinct group of armored jawless vertebrates |
| OST | type genus of the family Ostreidae |
| OST | large native of Japan introduced along United States Pacific coast |
| OST | oysters |
| OST | fast-running African flightless bird with two-toed feet |
| OST | tall fern of northern temperate regions having graceful arched fronds and sporophylls resembling ostrich plumes |
| OST | a member of the eastern group of Goths who created a kingdom in northern Italy around 500 AD |
| OST | deciduous monoecious trees of Europe and Asia and America |
| OST | medium-sized hop hornbeam of southern Europe and Asia Minor |
| OST | medium-sized hop hornbeam of eastern North America |
| OST | deciduous monoecious shrubs of China and Mongolia resembling trees of the genus Ostrya |