IBM Worklight skins provide support for multiple form factors in a single executable file for devices of the same OS family.
Different types of devices exist for a same environment. If you want to write a piece of code that is specific to a certain device, you must create a skin. Skin are sub-variants of an environment and they provide support for multiple form factors in a single executable file for devices of the same OS family. Skins are packaged together in one app. At run time, only the skin that corresponds to the target device is applied.
Source Help - IBM Worklight IBM Worklight skins.
