A.K.A.
mush ball,
big ball, or
kitten ball
Softball is similar to baseball but is played with a larger and relatively softer ball. (Trust me it still hurts to get beaned with it.) Pitching is done underhand. Which leads to two basic forms of softball, fastpitch and slowpitch. There is also modifiedpitch softball but I don't know anything about that form. Other differences are that the dimensions of the field are smaller. Including the pitcher being closer to the batter. Most leagues do not allow stealing and a balk is not a free base.
Originally it was created as a softer, gentler form of baseball. Some claim as an indoor version of baseball others claim as a recreational sport in a vacant lot in Chicago. But fast pitch has evolved into every bit as tough and skillful as baseball. Skilled fastpitch pitchers can reach speeds of 70mph. Because of the closer proximity to the batter hitting this ball can be as hard as hitting a professional baseball pitcher's throw.
Softball is big time. There is a professional league, the Women's Pro Softball League (WPSL). There is the Amateur Softball Association (ASA), which is the national governing body for softball in the United States. Softball is a NCAA recognized collegiate sport. It is also popular at the high school level.
Softball is a very popular recreational sport. Every town I've ever lived in has leagues to play in. It is fairly cheap to get involved in the only major requirement is a glove. Although it is handy to have cleats, a softball, and a bat. Usually other people will have balls and bats. There are women's leagues, men's leagues, co-ed leagues, beer drinker leagues, senior leagues, youth leagues, etc.