Why are seated areas in sports stadiums called stands?

Answer 1

Originally all the areas where standing room only. There were no seated areas. Then as some clubs added a seated section normally used for VIPs, the rank and file were still placed in the standing areas as these were least expensive. Then following incidents where crowd volumes became high and there were significant "crush" injuries to those standing against the pitch-side wall and barrier-work randomly placed around the stand area laws were passed that forced clubs to replaces standing areas with seating. This was to stop overfill and those at the rear of the stand pushing forward on to those closer to the pitch.