A ball game played with a bat and ball between two teams of 9 players; teams take turns at bat trying to score run; "he played baseball in high school"; "there was a baseball game on every empy lot"; "there was a desire for National League ball in the area"; "play ball!".

Eearly19th century American newspapers would mention games listed as Bass-Ball, Base, Base Ball, Goal Ball and Town Ball. The first known printed record of a game that was slightly different from Rounders and resembled a game closer to Baseball, is from an 1829 book called The Boy's Own Book, in which the game is referred to as "Round Ball," "Base" and "Goal Ball."

A crude field diagram was included with specific locations for four stones or stakes (bases), that were arranged in a diamond. The article described how to "make an out" as well as how to get "home." The word "party" was used to describe a team, and the team at bat was called the "in-party." Each party pitched to themselves, bases were run in a clockwise direction and players could be put out by swinging and missing three pitched balls or by being hit with the ball while moving between bases.

The batter attempts to hit the baseball with a tapered cylindrical bat, made of wood (as required in professional baseball) or a variety of other materials (as allowed in many nonprofessional games). A team scores runs only when batting, by advancing its players--primarily via hits, walks, and the opposition team's fielding errors--counterclockwise past a series of three markers called bases and touching home plate arranged at the corners of a ninety-foot square, or "diamond." The game, played without time restriction, is structured around nine segments called innings. In each inning, both teams are given the opportunity to bat and score runs; a team's half-inning ends when three outs are recorded against that team.

Baseball on the professional, amateur, and youth levels is popular in North America, Central America, parts of South America, parts of the Caribbean, and parts of East Asia and Southeast Asia. The modern version of the game developed in North America beginning in the eighteenth century. The consensus of historians is that it evolved from earlier bat-and-ball games, such as rounders, brought to the continent by British and Irish immigrants. By the late nineteenth century, baseball was widely recognized as the national sport of the United States. The game is sometimes referred to as hardball in contrast to the very similar game of softball.