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