You have probably heard the term upright grand used before, but what does it mean? Is it really a grand that is upright? No, not possible! Back in the late 19th century, it originally referred to an upright piano with an overstrung scale, and called attention to the difference between the overstrung scale (where the bass strings are strung over the treble strings, a design that has been commonplace for well over 100 years), and the straight strung scale (a design that you just don't see any more, but was used extensively in the latter half of the 19th century, where the bass strings run parallel and on the same plane as the rest of the strings).
So...when the overstrung design was new, it made sense to call a vertical piano an "Upright Grand" to differentiate between that and the straight strung upright. It really had nothing to do with a grand piano, except that the overstrung design was used as in the grand piano. The "Upright Grand" designation actually stopped being used by manufacturers of any prominence by the late 1920's, but you still hear that designation used even today, but it really is meaningless...yet it did have an origin and a meaning at one time. And now you know!
