Baseman is a term commonly used in baseball to refer to a player who defends the area around the first, second, or third base. However, there are multiple synonyms that can be used to replace the word baseman. Some of these include first baseman, second baseman, third baseman, corner infielder, infielder, or baserunner. While these words all carry a degree of similarity in meaning, each has its own subtle distinctions that may be important to note. For example, a corner infielder typically specializes in playing first and third bases while a baserunner might be used to refer specifically to a player in the act of running between bases.