Socket adapters allow different plugs to connect to sockets of a different standard.
A-to-B Adapters convert an A socket into a B socket. That means that an American to Universal adapter converts an American socket to a Universal socket.
It’s not safe just because you can make it fit. Always check electrical tolerances and specifications before connecting any appliance to any socket, especially with an adapter. This will also prevent permanent damage to your devices and/or overloading.