A player's main character, often shortened to main, is the character a person uses the most often. For instance, Isai's main in Super Smash Bros. Melee is Captain Falcon. "Main" also can be used as a verb, e.g., "Ken Hoang mains Marth and Fox". In contrast, secondary characters are used in specific situations or just for casual play.
It is possible for a player to use more than one main character, though multiple mains are generally less common. In tournaments, multiple mains are more common with low tier mainers as they usually require more than one character in order to face all matchups.