Simple past tense and past participle of backpack.(verb)
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Use "backpacked" in a sentence
"Does anyone know if you shoot a deer in the deep woods and it's going to be a day before you get back out because you've backpacked in, what do you do to keep the meat good?"
"As I backpacked around Europe, I found myself standing in front of the Berlin Wall and looking at the white crosses memorializing those killed trying to escape the East."
"I lived in Hawaii for a long time in this little hut, surfed all of the time, backpacked and worked little odd jobs, then I moved to Nashville."