meg‧a‧lo‧ma‧ni‧a /ˌmeɡələʊˈmeɪniə $ -loʊ-/ noun [uncountable]
[Date: 1800-1900; Origin: megalo- 'large' (from Greek megas; ⇒ mega-) + mania]
when someone wants to have a lot of power for themselves and enjoys having control over other people’s lives, sometimes as part of a mental illness

[TahlilGaran] Dictionary of Contemporary English ▲