re- / Indo-European roots
Examples of words with the root re-: arrears, re-, rear guard, rearward, refoulement, reredos, retral, retro-.
Backward.Latin combining form conceivably from Indo-European *wret-, metathetical variant of *wert-, to turn (< "turned back"), an extended form of wer-2
1. re- from Latin re-, red-, backward, again.
2. Suffixed form *re(d)-tro-. retral, retro-; arrears, rear guard, rearward2, reredos from Latin retrō, backward, back, behind.
3. Suffixed form *re-ko- in Latin reciprocus (see per1)