The term embedded is typically used when talking about software hidden within a hardware appliance in a manner not normally seen. See "What 'embedding' means".
Software within your television, VCR, CD, MP3, DVD players, microwave, or router are all examples of some degree of embedding.
Tcl is frequently used for embedded systems.
RFox: Software embedded in devices that is not expected to be user configured is sometimes called (by me): "toasterware"