There is no 2nd party.
In the video game industry, many third parties publish the games they develop, such as Electronic Arts and Ubisoft, while others only develop games to be published under other companies, such as BioWare (2nd party Xbox and 3rd party PC) and Raven Software. Furthermore, third party developers can be owned by larger third parties, such as the relationship between Neversoft (creators of the Tony Hawk's Pro Skater series) and Activision. Because of this, much larger third parties that also publish their own games are typically referred to as publishing houses and not third party developers even though they do develop many of their own games internally.
Another example is a developer that is a separate legal entity from the software being used, usually providing an external software tool that helps organize or use information for the primary software product. Such tools could be a database, VoIP, or add-in interface software, among others.
"A third-party developer is a developer not directly tied to the primary product that a consumer is using. The primary product may be hardware or software."
Such as a third party (Paw Productions) creating an software/hardware for the 1st party developer (VSTEP, Ship Sim)