IGN is an abbreviation that stands for "In-Game Name". This is the name that a player uses while playing, and it may differ from their real name or even from their username on a specific gaming platform. In other words, it is a pseudonym that the player uses in the game. For example, on Steam, a user has a login / nickname to access the system. Within the platform, the player can choose any IGN (that does not violate the platform's rules).