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