Definition of oligarchize in US English:

oligarchize

(also oligarchise)

verb

  • with object To convert into an oligarchy; to subject to an oligarchy.

Origin

Mid 19th century; earliest use found in George Grote (1794–1871), historian and politician. From oligarchy + -ize.

Pronunciation

oligarchize

/ɒlɪˈɡɑːkʌɪz/