A hypothetical chemical element proposed in the 1860s to explain certain lines in the spectra of nebulae, later discovered to arise from forbidden transitions in oxygen and nitrogen ions.

]]>https://definedictionarymeaning.com/topic/85932/nebuliumRSS for NodeThu, 04 Jun 2026 05:11:26 GMTTue, 08 Jan 2019 08:30:06 GMT60