nineties noun 3adjective 1 noun[plural only]3 •The decade of one's life from age 90 through age 99. •The range between 90 and 99.My ideal bracket of temperature ranges from the sixties up to the nineties. •The decade of the 1890s, 1990s, etc.He and his clever staff of minor blackguards exploited to the full every weakness and caries in the London Society of the 'eighties, 'nineties, and 'oughts. — 1919 adjective1 •From or evoking the 91st through 100th years of a century (chiefly the 1990s).I found myself attracted to his mullet even though it struck me as needlessly nineties.
