What does the RMS in RMS Titanic stand for?

Answer 1

An ordinary ship would be SS (Steam Ship) or MV (Motor Vessel). RMS is Royal Mail Ship -( not only a steam ship, a sailing vessel can be RMS as well ) It's a distinction because of the carriage of the mail.

Answer 2

RMS Titanic stands for Royal Mail Ship.

Or it can mean royal mail steamer and royal merchant ship or steamer.

The Titanic was also called SS Titanic with the SS standing for Steam Ship.
RMS stands for Royal Mail Ship. But she only took on that status when she loaded the mail. Until that moment she was SS Titanic (steamship) like during sea trials, for example.

Answer 3

R.M.S stands for Royal Mail Ship, a designation for British ships carrying mail across the Atlantic.