According to Wikipedia’s article on Video Game Development Parties, a third-party game developer is a game developer that is not part of any particular first party console developer. Notable third-party companies include Electronic Arts, Activision, and Ubisoft.

Examples of usage:

· “Third-party developers make some awesome games, but I’ve been looking forward to first-party titles, recently.”

· “The third-party developers had quite the showing at this year’s E3.”

References: Retrieved on 6/25/2012.