| IRIDIUMS | • iridiums n. Plural of iridium. • IRIDIUM n. a metallic element. |
| ONCIDIUMS | • oncidiums n. Plural of oncidium. • ONCIDIUM n. any of a genus of tropical orchidaceous plants. |
| PERIDIUMS | • peridiums n. Plural of peridium. • PERIDIUM n. the outer coating of the spore carrier of a fungus. |
| RUBIDIUMS | • rubidiums n. Plural of rubidium. • RUBIDIUM n. a metallic element. |
| VENIDIUMS | • venidiums n. Plural of venidium. • VENIDIUM n. a plant native to South Africa with yellow or cream flowers, aka Cape Daisy. |
| CYMBIDIUMS | • cymbidiums n. Plural of cymbidium. • CYMBIDIUM n. a kind of tropical orchid. |
| PRESIDIUMS | • presidiums n. Plural of presidium. • PRESIDIUM n. (Latin) a standing committee in the former Soviet Union, also PRAESIDIUM. |
| RHIPIDIUMS | • RHIPIDIUM n. a fan-shaped cymose inflorescence. |
| OSMIRIDIUMS | • osmiridiums n. Plural of osmiridium. • OSMIRIDIUM n. a very hard corrosion-resistant white or grey natural alloy of osmium and iridium, also IRIDOSMINE, IRIDOSMIUM. |
| PRAESIDIUMS | • praesidiums n. Plural of praesidium. • PRAESIDIUM n. (Latin) a standing committee in the former Soviet Union. |
| CLOSTRIDIUMS | • CLOSTRIDIUM n. any of a genus of spore-forming mostly anaerobic soil or intestinal bacteria. |
| PLATINIRIDIUMS | • PLATINIRIDIUM n. an alloy of platinum and iridium. |