Plasma Workspaces is the umbrella term for all graphical environments provided by KDE.

Plasma Workspaces is the umbrella term for all graphical environments provided by KDE.

Three Plasma sub-projects are currently being developed: Plasma Desktop for traditional desktop PCs and notebooks, Plasma Netbook for netbooks,[3] and Plasma Active for Tablet PCs, Nokia N900 style smartphones and similar devices.

from http://en.wikipedia.org/wiki/KDE_Plasma_Workspaces