"Glass Cockpit, as a term, refers to the large LCD displays that are used in such avionics equipment. These are glass displays, some LCD and some LED or touchscreen, like that of a mobile phone or tablet. But fundamentally it is a term used to describe the higher use of glass panels in this type of avionics equipment, over that of older analog gauge, or small display products.

A glass cockpit doesn’t have to be just glass panels, but can be made up of gauges, radios and other avionics stack equipment, but, should there be a large Primary Flight Display or Multi Function Display (PFD/MFD) this will then define it as a glass cockpit.

I hope this helps."