| Word | Definitions | Synonyms |
|---|---|---|
| orogeny | (noun) the process of mountain formation (especially by the upward displacement of the earth's crust) | - |
| orograph | (noun) A machine for use in making topographical maps. | - |
| orography | (noun) the science of mountains | Synonyms: orology |
| oroide | (noun) alloy of copper and tin and zinc; used in imitation gold jewelry | Synonyms: oreide |
| orology | (noun) the science of mountains | Synonyms: orography |
| oropharynx | (noun) cavity formed by the pharynx at the back of the mouth | - |