Ensign noun – A piece of cloth with a special design that is used as an emblem or for signaling.
Usage example: fittingly, the organization promoting the welfare of marine life features a dolphin on its ensign
Standard is a synonym for ensign in flag topic. In some cases you can use "Standard" instead a noun "Ensign", when it comes to topics like substitute, emblem, pennant. popular alternative
The same thing happened to USS Blue (DD-387); again only 4 ensigns were on board (must have been the standard officer duty section) and they got underway and operated for 30 hours with an ensign in command, attacking two submarines and shooting down 5 Japanese airplanes.