Verb (5-dan, す, transitive)
1. to turn up (hem, sleeves, etc.); to fold back (e.g. a page)
Verb (5-dan, す, intransitive)
2. to turn back; to double back; to return
3. to enter (the second half; e.g. of a match)
4. to do immediately (e.g. call back, answer an email); to do right away
adverbially as 折り返して
Verb (5-dan, す, transitive)
Computing
5. to loopback (a signal, message, etc.)