The Free On-line Dictionary of Computing (30 December 2018):

normal order reduction

   Under this evaluation strategy an expression is evaluated by
   reducing the leftmost outermost redex first.  This method
   will terminate for any expression for which termination is
   possible, whereas applicative order reduction may not.  This
   method is equivalent to passing arguments unevaluated because
   arguments are initially to the right of functions applied to
   them.  See also computational adequacy theorem.