Simple past tense and past participle of harken.(verb)
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Use "harkened" in a sentence
"The publication's name harkened back to early traditions at the school."
"The episode kind of harkened back to The Prisoner in some ways, but then it also seemed a bit off at times."
"As SAT harkened back to its old abbreviation, millions naturally found themselves recalling it, and so thinking of the new test as the “Scholastic Assessment Test Reasoning Test.”"