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to turn up (hem, sleeves, etc.); to fold back (e.g. page)
to turn back; to double back; to return
to loopback (a signal, message, etc.)
電話が途中で切れたので折り返して掛け直した。
The call was cut off, so I called back.
マラソンコースの折り返し地点で給水を受けた。
I received water at the turnaround point of the marathon course.
担当者が不在のため、後ほど折り返します。
The person in charge is away, so I'll call back later.