diff --git a/grudge/symbolic/mappers/__init__.py b/grudge/symbolic/mappers/__init__.py
index 9c08abb05cf113371ec0fe6ca071a39b74818e37..e47214d1b88950ae32310e1ac4437f2ec1c72358 100644
--- a/grudge/symbolic/mappers/__init__.py
+++ b/grudge/symbolic/mappers/__init__.py
@@ -616,13 +616,13 @@ class StringifyMapper(pymbolic.mapper.stringifier.StringifyMapper):
     # {{{ global differentiation
 
     def map_diff(self, expr, enclosing_prec):
-        return "Diffx%d%s" % (expr.xyz_axi, self._format_op_props(expr))
+        return "Diffx%d%s" % (expr.xyz_axis, self._format_op_props(expr))
 
     def map_minv_st(self, expr, enclosing_prec):
-        return "MInvSTx%d%s" % (expr.xyz_axi, self._format_op_props(expr))
+        return "MInvSTx%d%s" % (expr.xyz_axis, self._format_op_props(expr))
 
     def map_stiffness(self, expr, enclosing_prec):
-        return "Stiffx%d%s" % (expr.xyz_axi, self._format_op_props(expr))
+        return "Stiffx%d%s" % (expr.xyz_axis, self._format_op_props(expr))
 
     def map_stiffness_t(self, expr, enclosing_prec):
         return "StiffTx%d%s" % (expr.xyz_axis, self._format_op_props(expr))