What was the rome-Berlin axis pact?

The "Rome-Berlin Axis" was used to describe the military coalition of Italy and Germany in 1939 under the Pact of Steel signed by Mussolini and Hitler. This is the source of the term Axis Powers to describe their alliance. With the signing of the Tripartite Pact by Japan (1940), the "Rome-Berlin-Tokyo Axis" describes the three major powers that fought the Allied Powers in World War 2.