There are as many different styles of bowling shirts as there are different styles of bowlers. The shirts range all the way from simple t-shirts with pictures up to glitzy shirts from the past.
A true bowling shirt is a box cut, short sleeved, with a button up front, pocket, and small collar. Most bowling shirts are very colorful, with panels of different colors, such as black and red. They also have piping along the shoulders.
They are usually made of a cotton/polyester blend. Charlie on the Two and Half Men TV show is fond of wearing bowling shirts for every occasion. Bowling is enjoyed by about 100 million people over several continents.
There are also team shirts which league bowlers favor as they can be customized with the team name, etc. Often referred to as "retro bowling shirts", older bowling shirts from the 40s, 50s, and 60s are very sought after by collectors.