Flower power is an old-fashioned way of referring to hippies and the culture associated with hippies in the late 1960s and early 1970s.
...the era of flower power.
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FLOWER POWER
Meaning of FLOWER POWER in English
Collins COBUILD Advanced Learner's English Dictionary. Английский словарь Коллинз COBUILD для изучающих язык на продвинутом уровне. 2006