A home run is a four-base hit clearing the bases. It is abbreviated as HR. Every runner scores including the batter. A home run usually is hit out of the park, beyond the outfield fence, but it is also possible to hit an inside-the-park home run. A home run hit with the bases loaded is a grand slam.
There are a variety of ways to set records with home runs. The major league record for the most home runs in a single game is four (held by 18 players - see list below). The major league record for the most consecutive games in which a home run has been hit by a player is eight (held by Ken Griffey Jr., Dale Long, and Don Mattingly). The major league record for the most home runs in a single season is 73 (Barry Bonds). The major league record for the most home runs in a single season in the American League is 61 (Roger Maris). The major league record for most seasons as the season home run champ is 12, held by Babe Ruth. The modern major league record for fewest home runs in a season by the league leader is 7 (held by several players). The major league record for most home runs in a season by a pitcher is 9 (Wes Ferrell). The major league record for most home runs in a season by a pinch hitter is 7 (Craig Wilson and Dave Hansen). The major league record for the most home runs in a single season against a single opponent is 14 (Lou Gehrig, against the 1936 Cleveland Indians).
|All Time Leaders|
|Game||17 - see below||4|
|Negro League Career||Mule Suttles||237|
|Negro League Season||Willie Wells||27|
|Negro League Season||Mule Suttles||27|
|NPB Career||Sadaharu Oh||868|
|NPB Season||Wladimir Balentien||60||2013|
|NPB Game||Yoshiyuki Iwamoto||4|
|NPB Game||Sadaharu Oh||4|
|NPB Game||Tony Solaita||4|
|NPB Game||Nigel Wilson||4|
|NPB Game||Atsuya Furuta||4|
|Minor League Career||Hector Espino||484|
|Minor League Season||Joe Bauman||72|
|Minor League Game||Nig Clarke||8|
|Cuban Season||Alfredo Despaigne||36||2011-2012|
|Cuban Game||Leonel Moa||4|
|Cuban Game||Alberto Díaz||4|
|Cuban Game||Omar Linares||4|
|KBO Career||Seung-yeop Lee||358+|
|KBO Season||Seung-yeop Lee||56|
|CPBL Season||Tilson Brito||33|
|Hoofdklasse Career||Marcel Joost|
|Hoofdklasse Season||Jacky Jakoba||24|
|Serie A1 Season||Donald Mazzilli||33|
|AAGPBL Career||Eleanor Callow||55|
|AAGPBL Season||Joanne Weaver||29|
Four home runs in one game
For a full list, see List of nicknames for a home run.
- Ed Eagle: "Players with 4 home runs in a game", mlb.com, September 5, 2018. 
- Christopher D. Green: "Baseball's First Power Surge: Home Runs in the Late 19th-Century Major Leagues", The Baseball Research Journal, SABR, Volume 40, Number 2 (Fall 2011), pp. 99-103.
- Bill Jenkinson: Baseball's Ultimate Power: Ranking the All-Time Greatest Distance Home Run Hitters, Lyons Press, Guilford, CT, 2010. ISBN 1599215446
- Bob McConnell and David Vincent: SABR Presents the Home Run Encyclopedia: The Who, What, and Where of Every Home Run Hit Since 1876, SABR, Macmillan, New York, NY, 1996. ISBN 002860816X
- Joshua Shifrin and Tommy Shea: Dingers: The 101 Most Memorable Home Runs in Baseball History, Sports Publishing LLC, New York, NY, 2016. ISBN 978-1-6132-1831-0
- Christian Trudeau: "Out of Here: Home Runs in Canada", The Baseball Research Journal, SABR, Volume 40, Number 2 (Fall 2011), pp. 73-78. 
- David Vincent: Home Run: the Definitive History of Baseball's Ultimate Weapon, Potomac Books, Inc., Dulles, VA, 2007.
- David Vincent: Home Run's Most Wanted: The Top 10 Book of Monumental Dingers, Prodigious Swingers, and Everything Long-Ball, Potomac Books, Inc., Dulles, VA, 2009.
- David Vincent: "Pitchers Dig the Long ball (At Least When They Are Hitting)", The Baseball Research Journal, SABR, Volume 41, Number 1 (Spring 2012), pp. 7-11. 
- Steven K. Wagner: The Four Home Runs Club: Sluggers Who Achieved Baseball's Rarest Feat, Rowman & Littlefield, Lanham, MD, 2018. ISBN 978-1-5381-1542-8