noun
- A trivalent metallic element of the rare earth group; occurs with yttrium.
- synonyms: erbium, atomic number 68
- A room in a hospital or clinic staffed and equipped to provide emergency care to persons requiring immediate medical treatment.
- synonyms: emergency room
WordNet 3.0 © 2006 by Princeton University
| APA | WordNet. (2010). er. Retrieved September 21, 2026, from http://smartdefine.org/er/definitions/1273345 |
| Chicago | WordNet. 2010. "er" http://smartdefine.org/er/definitions/1273345 (accessed September 21, 2026). |
| Harvard | WordNet 2010, er, Smart Define, viewed 21 September, 2026, <http://smartdefine.org/er/definitions/1273345>. |
| MLA | WordNet. "er" 23 October 2010. Web. 21 September 2026. <http://smartdefine.org/er/definitions/1273345> |