Taken from The Grove Concise Dictionary of Music...
Grand Pianoforte. A piano in a horizontal wing-shaped case of a form directly derived from the harpsichord's. The earliest recorded use of the term is a 1777 patent to Robert Stodart for a Harpsichord-Piano.
By the way, the first upright was invented and made by the Englishman John Isaac Hawkins in the very early 1800's.
This comment may have nothing to do with answering the question, but I am having the experience of refurbishing my old mum's 1905 German steel frame upright piano and am astounded at the complicatet arrangement of levers from the keyboard to the strings. The workmanship of each timber hammer has to be seen to be believed. Every squared piece of wood is slice cut, not sawn. And the intricantcy of the return springs, finer than a small sewing needle. Simply astounding.