Nouns ending in -s, -x, -z, -ch, or -sh add -es to form the plural. This makes the word easier to pronounce.
Arthritis is regular. It follows the -es Addition rule.
Use plural verbs: "The arthritises are ready" (not "is ready").
Yes. The plural arthritises is standard across all English variants.
The word arthritis follows the standard English pluralization rule. When forming the plural, arthritis becomes arthritises. This follows the -es Addition pattern, which is one of the most common plural rules in English.
Understanding why arthritis becomes arthritises helps with spelling and pronunciation. Nouns ending in -s, -x, -z, -ch, or -sh add -es to form the plural. This makes the word easier to pronounce.
When using arthritises in writing, remember that it functions as a plural noun in sentences. It pairs with plural verbs and pronouns. For example: "The arthritises are ready" (not "is ready"). This subject-verb agreement is essential for grammatical correctness.