I don't have enough reputation to do it myself, so please do.
Or vice versa, but former is better to me.
So, please, open http://stackoverflow.com/tags/read-eval-print-loop/synonyms and add http://stackoverflow.com/tags/repl to it.
Also copy tag-wiki from REPL to read-eval-print-loop. though hopefully SO engine can do it automagically when synonyms registered