–n. phr., an estimate, an estimate that is acceptable. The estimate may be for the number of people who went to an event, or it may be the amount of money that something will cost. A ballpark, of course, is a baseball field. This idiom comes from an earlier idiom, in the ballpark, which means “within a reasonable range.”
Examples:
We don’t know the exact costs yet, but I can give you a ballpark figure.
The travel agent was only able to offer a ballpark figure on how much the trip would cost.
Looking at some real ballpark figures, Kaufman Stadium in Kansas City, where Game 6 of the World Series will be played tonight, can hold 37,903 people. And that number shows only a portion of how many people will watch the game. There’s also TV. Games 4 and 5, held in San Francisco on Saturday and Sunday, had 10.7 million and 12.6 million U.S. TV viewers respectively.
Be sure and tune in tonight as the San Francisco Giants, leading the series 3-2, try to finish off the Kansas City Royals.