What is a win/place/show?

Win
A win bet involves selecting the horse that you think will finish the race in first place.

Place
With a place bet, you win if your selected horse finishes the race in either first or second place. A place bet normally pays less than a win bet on the same horse because the entire pool is split between two groups: those whose horse finished first and those whose horse finished second.

Show
With a show bet, you win if your selected horse finishes in first, second or third place. The show bet pool is split between three groups of people and pays less than a win or place bet on the same horse.