Source : Free On-Line Dictionary of Computing

read-eval-print loop
     
         (REPL) A programming {structure}
        within {LISP} which repeatedly reads a {form} from the {user},
        evaluates it, and displays the result.
     
        A read-eval-print {loop} forms the basis of the {Top-Level}
        {shell} that programmers of the LISP family of languages
        interact with.
     
        In many dialects of LISP a very simple REPL could be
        implemented as:
     
        	(loop (print (eval (read)))).
     
        (2003-06-23)