@georgia yeah medhyadesh basically- center of the country, as opposed to north (pahadi kashmir etc)
You may include madhya pradesh but that was actually called dakkhin apparently
Uttar Pradesh is a such a shitty name idk who came with it probably based on the abbrevation of united provinces.
Hind/hindi is both divorced from the culture imo a malignant and ruinous name (i call hindi and urdu vishabhasha for a reason, at least the obsession with their name or the obsession with the stuff thay led to it)
For the dehli dialect in particular id call it khadiboli, maybe kauravi or dehlavi (dillavi) which have a better historic relation