When a group or a decision is unanimous, it means that everyone is in total agreement. Just imagine if you let third graders vote on what to serve at lunch: Pizza and candy would be the unanimous choice!
The adjective unanimous comes from the similar Latin word unanimus, which means “of one mind.” So when people think unanimously, they all have the same idea in their heads. A vote is unanimous when all voters are in agreement. Said Marcus Cicero, “Great is the power, great is the authority of a senate that is unanimous in its opinions.”