- (n.) A rare metallic element associated with several other rare elements in the mineral gadolinite from Ytterby in Sweden. Symbol Er. Atomic weight 165.9. Its salts are rose-colored and give characteristic spectra. Its sesquioxide is called erbia.
- (n.) A metallic element of the rare earth group, found in gadolinite and some other minerals. Symbol, Er; at. wt. 167.4. Its salts are rose-colored and give characteristic spectra.
Webster's Revised Unabridged Dictionary
| APA | Webster's. (2011). erbium. Retrieved September 21, 2026, from http://smartdefine.org/erbium/definitions/2004515 |
| Chicago | Webster's. 2011. "erbium" http://smartdefine.org/erbium/definitions/2004515 (accessed September 21, 2026). |
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| MLA | Webster's. "erbium" 27 May 2011. Web. 21 September 2026. <http://smartdefine.org/erbium/definitions/2004515> |