The Marvel Multiverse: Earth-199999

In order to acknowledge and address differences between the realities where comics occur it was decided to assign them a number. The Marvel Cinematic Universe events all transpire in a reality designated 'Earth-199999'

This is intended to allow for potential multiverse development in future while acknowledging that the Marvel Cinematic Universe, while adapting from comics, is not a direct adaptation of the comics they are sourcing. This allows for the franchise to take creative liberties with its characters without relying entirely on the pre-existing lore of the comics.

Earth-199999 while on a fundamental level applies similar mechanics as our reality, expands upon them most notably in the mythology of Thor and the nature of science eventually reaching the stage where it is indistinguishable from magic. This forms a method enabling magical actions in the MCU to be accepted as an evolution of technology without breaking the suspension of disbelief and in the process maintaining narrative consistency with its world when introducing more mystical or normally non-believable aspects such as the magical abilities of the Sorcerer Supreme, Doctor Strange.

While it's worth acknowledging that the events of the Marvel Cinematic Universe are set in a particular reality, the nature of the MCU multiverse currently has not been explored, though this is set to change, meaning confusion is not as much of issue when dealing with the differing realities.