"pertaining to or of the nature of government by a few," 1640s, from Greek oligarkhikos "pertaining to oligarchy," from oligarkhos, related to oligarkhia "government by the few" (see oligarchy). Related: Oligarchical.
oleomargarine
olfaction
olfactory
Olga
oligarch
oligarchic
oligarchy
oligo-
Oligocene
oligopolistic
oligopoly