A mandate is an official order or commission to do something. "a mandate to seek the release of political prisoners". To have a mandate is to have, or to have been given by another power or government, the authority to carry out a policy or course of action. Synonyms: instruction · directive · direction · decree · command · order.
A Mandate (capitalized) is a former colony that is being supervised by that colonial power, or another intervening power, as it converts into a newly independent nation. "The British Mandate" in Palestine, before Israeli independence.