C++: What is the difference between std::map and std::multimap?

1// map — unique keys
2std::map<int, std::string> m;
3m[1] = "one";
4m[1] = "uno";  // Overwrites
5
6// multimap — duplicate keys
7std::multimap<int, std::string> mm;
8mm.insert({1, "one"});
9mm.insert({1, "uno"});  // Both stored
10mm.count(1);  // 2