Steam with its temperature raised above that of saturation. The temperature in excess of its saturation temperature is referred to as superheat.

Steam at a higher temperature than its saturation temperature.

Steam heated at constant pressure out of contact with the water from which it was formed, i.e., at a higher temperature than that of saturation.

Steam taken directly from a boiler retains the same temperature and pressure as when it was produced and is said to be "saturated". By taking such steam and heating it further, a much greater volume of gas can be produced for a small amount of extra heat. Tests have shown that superheating can result in a 25% economy in coal and 30% in water. Introduced in the 1900's and used mainly on the larger main-line engines. Superheated steam will always be dry. Search for steam table books on Amazon.co.uk

Steam which is hotter than boiling temperature for a given pressure.

Steam at a given pressure which is above the temperature which corresponds to boiling temperature at that given pressure.

dry saturated steam that is further heated to increase its temperature at the same pressure

Steam at higher temperature than its saturation (condensing) temperature.

Increased thermal efficiency is raised by boilers that are used for steam-driven turbine-generators units, which incorporate superheaters to raise steam to a higher temperature than its saturation temperature.