Typo.

Doc/ref/ref6.tex

@@ -346,7 +346,7 @@ name is unbound, a \exception{NameError} exception will be raised.
 \indexii{unbinding}{name}
 
 It is illegal to delete a name from the local namespace if it occurs
-as a free variable\indexii{free}{varaible} in a nested block.
+as a free variable\indexii{free}{variable} in a nested block.
 
 Deletion of attribute references, subscriptions and slicings
 is passed to the primary object involved; deletion of a slicing