The terms you've listed refer to a specific, historical version of the reFX Nexus 2
The "AIR" tag refers to a famous cracking group. This version was released years ago to bypass the USB eLicenser (dongle) requirement that originally used for copy protection. Stability Issues: Refx nexus 2.2.1 AIR eLicenser 2.2.1
Today, reFX Nexus 2.2.1 and the AIR emulator are considered obsolete. The terms you've listed refer to a specific,
AIR eLicenser 2.2.1, on the other hand, appears to be a licensing and authorization tool developed by Avid (formerly known as Digidesign) in partnership with eLicenser. on the other hand
What is Refx Nexus 2.2.1?