We tend to think of a dollar as a piece of printed paper, a banknote, I guess it is called. But when a dollar could buy a lot more than it can these days, the dollar used to be a silver coin.
The various designs of coins in general are often named after the designer of the graphics that are on the coin. In the case of Morgan dollars, that was George T Morgan. Many of the coins were subsequently melted down, to make newer coins. This made the remaining coins even more collectible. There was also a release of older coins, that chaged the pricing structure, and also placed a lot of uncirculated, and higher quality coins onto the market, but the manufacture of Morgan dollars ended in the 1920's, making cheap morgan dollars a bit harder to find, and stabilizing the prices to make them a good investment.