In baseball, a home run (abbreviated HR) is scored when the ball is hit in such a way that the batter is able to circle the bases and reach home plate safely in one play without any errors being committed by the defensive team. A home run is usually achieved by hitting the ball over the outfield fence between the foul poles (or hitting either foul pole) without the ball touching the field. Far less common is the "inside-the-park" home run where the batter reaches home safely while the baseball is in play on the field.
When a home run is scored, the batter is credited with a hit and a run scored, and a run batted in (RBI) for each runner that scores, including himself. Likewise, the pitcher is recorded as having given up a hit and a run, with additional runs charged for each runner that scores other than the batter.
Home runs are among the most popular aspects of baseball and, as a result, prolific home run hitters are usually the most popular among fans and consequently the highest paid by teams—hence the old saying, "Home run hitters drive Cadillacs, and singles hitters drive Fords" (coined, circa 1948, by veteran pitcher Fritz Ostermueller, by way of mentoring his young teammate, Ralph Kiner).
Nicknames for a home run include "homer", "round tripper", "four-bagger", "big fly", "dinger", "long ball", "jack", "shot"/"moon shot", "bomb", and "blast", while a player hitting a home run may be said to have "gone deep" or "gone yard".