Nouns ending in a consonant followed by -y change the -y to -ies in the plural form.
Courtesy is regular. It follows the -ies Conversion rule.
Use plural verbs: "The courtesies are ready" (not "is ready").
Yes. The plural courtesies is standard across all English variants.
The word courtesy follows the standard English pluralization rule. When forming the plural, courtesy becomes courtesies. This follows the -ies Conversion pattern, which is one of the most common plural rules in English.
Understanding why courtesy becomes courtesies helps with spelling and pronunciation. Nouns ending in a consonant followed by -y change the -y to -ies in the plural form.
When using courtesies in writing, remember that it functions as a plural noun in sentences. It pairs with plural verbs and pronouns. For example: "The courtesies are ready" (not "is ready"). This subject-verb agreement is essential for grammatical correctness.