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

lvalue

    A reference to a location, an expression which
   can appear as the destination of an assignment operator
   indicating where a value should be stored.  For example, a
   variable or an array element are lvalues but the constant 42
   and the expression i+1 are not.  A constant string may or may
   not be an lvalue (it usually is in C).

   (1995-04-28)