| Word | Definitions | Synonyms |
|---|---|---|
| radome | (noun) a housing for a radar antenna; transparent to radio waves | Synonyms: radar dome |
| radon | (noun) a radioactive gaseous element formed by the disintegration of radium; the heaviest of the inert gasses; occurs naturally (especially in areas over granite) and is considered a hazard to health | Synonyms: atomic number 86, Rn |