Alternative letter-case form of Sixties (The decade of the 1860s, 1960s, etc.)
I remember living through the sixties.
During the sixties [1860s] the Sabbatarians were particularly active in their attacks on Sunday excursions, and this had an effect both on the companies and the public.1954 June, R. Marchant, “Early Excursion Trains”, in Railway Magazine, page 427:
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The decade of one's life from age 60 through age 69.
She retired at some point in her sixties, I don't recall exactly when.
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Temperature The range between 60 and 69 Fahrenheit.
From or evoking the 61st through 70th years of a century (chiefly the 1960s).
She coughed as she exhaled. Sixties weed had been nowhere near this strong.
Historians do not rely on single bits of evidence, but are always seeking corroboration, qualification, correction. These novels, set in context, are in themselves interesting fragments of sixties culture.1993, Arthur Marwick, “Six Novels of the Sixties — Three French, Three Italian”, in Journal of Contemporary History, volume 28, number 4, →DOI, page 588:
Sixties
noun
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The decade of the 1860s, 1960s, etc. (but especially the 1960s)
Occasionally this was a direct result of network attitudes — as in the fifties with integration, the sixties with Vietnam, or the seventies with Watergate.1981, Channels of Communications, page 22:
Both Burnham and the president were middle-aged baby boomers with an investment in their Sixties youth[…]2016, Oliver Gruner, Screening the Sixties, →ISBN, page 179:
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2017 https://www.independent.co.uk/news/long_reads/sixties-decade-was-it-good-sexual-revolution-swinging-london-hippies-culture-music-art-germaine-a7946506.html When asked what the Sixties were all about, most people reply: peace, love, happiness.
Counterculture expert James Riley delves into the darkness of the Sixties to sort fact from psychedelic fiction.2019 https://www.cam.ac.uk/research/discussion/did-the-sixties-dream-die-in-1969
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US A period in American history centered around the counterculture movement of the late 1960s.
The 1960s and the first half of the 1970s—an era known as "the sixties" to most observers—has perhaps generated more mythology than any other period in American history.1999, Andrew E. Hunt, “Introduction”, in The Turning: A History of Vietnam Veterans Against the War, →ISBN, page 1:
But the sixties no more ended in 1969 than they began in 1960.2011, Rob Kirkpatrick, 1969: The Year Everything Changed, page xvii:
1 more example
It is relatively easy to choose some event (Kent State, Altamont, Watergate, and the fall of Saigon are favorites) as the end of the Sixties[…]2013, James J. Farrell, The Spirit of the Sixties, page 17: