A master electrician is someone who has moved past the apprentice and journeyman stages of their career. ... A journeyman electrician will not have the same experience or licenses as a master electrician. Journeymen may be able to work independently, but do not have complete autonomy.
Basically, just experience, and a different license.
Journeyman would be in my eyes, when I finished my apprenticeship, I was considered an improver for a year after. Qualified, but still needed to pass designs etc through someone more senior.