a whole new ball game

a (whole) new ballgame

A situation that is completely different from what one is used to or expecting. Living away from home is a whole new ballgame for most young adults. I used to babysit, but having a child of my own is a new ballgame.
See also: ballgame, new

a whole new ball game

Some thing or situation that is very different to, and often more difficult or complicated than, something else. It's one thing to babysit your friends' kids from time to time, but having your own children is a whole new ball game. I know you think you're some hotshot just because you worked in television once, but working on a film is a whole new ball game.
See also: ball, game, new, whole
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.

a whole new ball game

or

a different ball game

If you describe a situation as a whole new ball game, or a different ball game, you mean that it is completely different from what came before. I'm working with kids now, which is a whole new ball game. If military force were to be used, then that would be a completely different ball game. Note: `Ball game' is often used in American English to refer to a game of baseball.
See also: ball, game, new, whole
Collins COBUILD Idioms Dictionary, 3rd ed. © HarperCollins Publishers 2012

a whole new ball game

a completely new set of circumstances. informal
The phrase originated in North America, where a ball game is a baseball match.
1989 Looks Making the film was a whole new ball game…for Kylie.
See also: ball, game, new, whole
Farlex Partner Idioms Dictionary © Farlex 2017

a whole new ball game

n. a completely different situation; something completely different. Now that you’re here, it’s a whole new ball game.
See also: ball, game, new, whole
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions Copyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved.

whole new ball game/ball of wax, a

An entirely changed situation. The first, an Americanism originating about 1970, applied the idea of a new sport with different rules to changed circumstances in almost any situation: for example, “If this were to happen, some official of our government would no doubt announce that we were in a ‘whole new ballgame,’ which would mean that none of the policies or promises made in the past were binding any longer” (New Yorker, 1971). It is also put as a whole other ball game. The second phrase, which has exactly the same meaning, may, it has been suggested, come from a seventeenth-century English legal practice whereby land was divided among several heirs. Wax was used to cover small pieces of paper on which portions of land were identified; each was rolled into a ball, and the balls were drawn from a hat by the heirs in order of precedence (the eldest first, the youngest last). Whether or not this was the source, “the whole ball of wax” today also means all the elements of a plan, situation, or action, as well as all related elements. Thus one might say, “He sold her his house, his boat, his car—the whole ball of wax.”
See also: ball, game, new, of, whole
The Dictionary of Clichés by Christine Ammer Copyright © 2013 by Christine Ammer
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References in periodicals archive ?
Burk, Never Just a Game: Players, Owners, and American Baseball to 1920 (Chapel Hill, 1994), Goldstein, Playing for Keeps, 134-149; Allen Guttmann, A Whole New Ball Game: An Interpretation of American Sports (Chapel Hill, 1988), 61-69; William A.
(27.) See Burk, Never Just a Game, 207-209; Guttmann, A Whole New Ball Game, 65- 69; Lowenfish, Imperfect Diamond, 88-90; Seymour, The Golden Age, 212, 230-34; and Voigt, American Baseball, vol.
Even though he knew a lot about collecting, he found himself in a whole new ball game when he started Ultimate Line-Up Inc., the only African American-owned company licensed to produce Major League Baseball and National Hockey League card games.
Baker, Sports in the Western World (Urbana, 1988); Allen Guttmann, A Whole New Ball Game: An Interpretation of American Sports (Chapel Hill, 1988); Melvin Adelman, A Sporting Time: New York City and the Rise of Modern Athletics, 1820-70 (Urbana, 1986); Richard Mandell, Sport: A Cultural History (New York, 1984); and Benjamin Rader, American Sports: From the Age of Folk Games to the Age of Spectators (Englewood Cliffs, 1983).