IPA: /ˌʌltɪˈmeɪtəm/
KK: /ʌltəˈmeɪtəm/
A final demand or statement of terms that one party gives to another, which must be accepted or faced with consequences.
The company issued an ultimatum to the workers, stating they must accept the new contract or face layoffs.
Ultimatum → It is formed from "ultimus" (meaning last) and the suffix "-um" (used to form nouns). The word "ultimatum" refers to a final demand or statement of terms, indicating that it is the last condition that must be met.
Think of 'last' ('ultimus') to remember that an 'ultimatum' is a final demand or condition.