Depending on its usage, it may mean either "master" or "slave," or it may mean one who is most fit for a specific position of honor and prestige. Derived from the adjective awla (one who is best qualified), it means: the person who is best suited to be the religious and temporal leader of all Muslims.
MEVLA
Meaning of MEVLA in English
Advanced Islamic English dictionary. Расширенный исламский словарь английского языка. 2012