diff --git a/.Attic/metta_lang/metta_eval.pl b/.Attic/metta_lang/metta_eval.pl
index cf378f7a3d..ac2c67d1bf 100755
--- a/.Attic/metta_lang/metta_eval.pl
+++ b/.Attic/metta_lang/metta_eval.pl
@@ -175,7 +175,7 @@
 
 eval_reducable(Eq,RetType,Depth,Self,X,G,Y,O):- catch_metta_return(G,Y), return_x_g_y(Eq,RetType,Depth,Self,X,X,Y,O).
 
-return_x_g_y(_Eq,_RetType,_Depth,_Self,X,_,Y,R):- Y == 'NotReducable',!,R=X.
+return_x_g_y(_Eq,_RetType,_Depth,_Self,X,_,Y,R):- Y == 'NotReducible',!,R=X.
 return_x_g_y(Eq,RetType,Depth,    Self,X,M,Y,R):- M\=@=Y, !, eval_args(Eq,RetType,Depth,Self,Y,Z), return_x_g_y(Eq,RetType,Depth,Self,X,Y,Z,R).
 return_x_g_y(_Eq,_RetType,_Depth,_Self,_X,_M,R,R).
 
@@ -2862,7 +2862,7 @@
   ((eval_args(Eq,RetType,Depth,Self,Funcall,E))
     *-> is_returned(E);(fail,E=Funcall)).
 
-is_returned(E):- notrace( \+ is_empty(E)), nop(assertion(E \== 'NotReducable')).
+is_returned(E):- notrace( \+ is_empty(E)), nop(assertion(E \== 'NotReducible')).
 is_empty(E):- notrace(( nonvar(E), sub_var('Empty',E))),!.
 
 
diff --git a/prolog/metta_lang/metta_eval.pl b/prolog/metta_lang/metta_eval.pl
index c427234d33..3ddd6ff652 100755
--- a/prolog/metta_lang/metta_eval.pl
+++ b/prolog/metta_lang/metta_eval.pl
@@ -79,7 +79,7 @@
 self_eval0('Empty').
 self_eval0([]).
 self_eval0('%Undefined%').
-self_eval0(X):- atom(X),!, X\=='NotReducable', \+ nb_bound(X,_),!.
+self_eval0(X):- atom(X),!, X\=='NotReducible', \+ nb_bound(X,_),!.
 
 nb_bound(Name,X):- atom(Name), % atom_concat('&', _, Name),
   nb_current(Name, X), compound(X). % spaces and states are stored as compounds
@@ -307,7 +307,7 @@
 
 eval_20(Eq,RetType,_Dpth,_Slf,Name,Y):-
     atom(Name), !,
-      (Name=='NotReducable'->throw(metta_NotReducable);
+      (Name=='NotReducible'->throw(metta_NotReducible);
       (nb_bound(Name,X)->do_expander(Eq,RetType,X,Y);
        Y = Name)).
 
@@ -2807,7 +2807,7 @@
 
 eval_defn_choose_candidates(Eq,RetType,Depth,Self,X,Y):-
     findall((XX->B0),get_defn_expansions(Eq,RetType,Depth,Self,X,XX,B0),XXB0L),!,
-    catch(eval_defn_bodies(Eq,RetType,Depth,Self,X,Y,XXB0L),metta_NotReducable,X=Y).
+    catch(eval_defn_bodies(Eq,RetType,Depth,Self,X,Y,XXB0L),metta_NotReducible,X=Y).
 eval_defn_choose_candidates(Eq,RetType,Depth,Self,X,Y):-
     eval_defn_bodies(Eq,RetType,Depth,Self,X,Y,[]),!.