Kalimdor is the name given to the Western continental land mass. It was also the name of the progenitor continent which was broken into the two known continental masses and the leser bodies in between in the event known as the Great Sundering. In the primal ages, Kalimdor may have been the name used for the world in the way Azeroth is used now. Kalimdor is the name given to the Western continental land mass.
On the Wyrmrest Accord server, /kalimdor is an out of character chat channel to promote roleplay on said continent. It exists on both Horde and Alliance factions.