Simple past tense and past participle of picnic.(verb)
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Use "picnicked" in a sentence
"Amid the medieval domes and balconies overlooking a water tank, families picnicked, young couples whispered, children played ball, and young men attended prayer meetings."
"Nana and I had picnicked here a few times in my childhood."
"Last year, I picnicked on the grass with my boss Stephanie and all her friends -- a birthday to remember, especially when the sky opened up during the orchestra's last aria, and dumped rain on all of us innocent, umbrella-less concert goers."