Countable Nouns That Start with O and End with TIS

Explore 7 verified English countable nouns starting with O and ending with TIS, including Osteomyelitis, Ovotestis, Onychitis, Orchiepididymitis, Ophthalmomyositis, Ophthalmoneuritis and Olecranarthritis. Sort these count nouns with singular and plural forms by word length for ESL grammar practice, determiner usage, and plural spelling below, or review singular and plural count rules in our noun grammar guide.