(n.) A rare metallic element, of the same group as platinum, which it much resembles, being silver-white, but harder, and brittle, and indifferent to most corrosive agents. With the exception of osmium, it is the heaviest substance known, its specific gravity being 22.4. Symbol Ir. Atomic weight 192.5.
Webster's Revised Unabridged Dictionary
| APA | Webster's. (2011). iridium. Retrieved September 21, 2026, from http://smartdefine.org/iridium/definitions/2023641 |
| Chicago | Webster's. 2011. "iridium" http://smartdefine.org/iridium/definitions/2023641 (accessed September 21, 2026). |
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| MLA | Webster's. "iridium" 27 May 2011. Web. 21 September 2026. <http://smartdefine.org/iridium/definitions/2023641> |