IPA: /ˌmɛɡəloʊˈmeɪniə/
KK: /ˌmɛɡəloʊˈmeɪniə/
A mental condition where a person has an extreme desire for power, wealth, or importance, often with unrealistic beliefs about their own abilities or influence.
His megalomania led him to believe he could control everything around him.
Megalomania → It is formed from "megalo-" (from Greek "megalos", meaning large or great) and "mania" (from Greek "mania", meaning madness or obsession). The word describes an obsession with great or extravagant things, often relating to power or wealth.
Think of 'great' ('megalo-') and 'madness' ('mania') to remember that megalomania refers to an obsession with greatness.