@@ -210,18 +210,18 @@ def update(self, data):
         """
         data = np.atleast_1d(np.array(data, dtype=object))
 
-        # check if convertable to number:
-        convertable = True
+        # check if convertible to number:
+        convertible = True
         for val in OrderedDict.fromkeys(data):
             # OrderedDict just iterates over unique values in data.
             if not isinstance(val, (str, bytes)):
                 raise TypeError("{val!r} is not a string".format(val=val))
-            if convertable:
-                # this will only be called so long as convertable is True.
-                convertable = self._str_is_convertible(val)
+            if convertible:
+                # this will only be called so long as convertible is True.
+                convertible = self._str_is_convertible(val)
             if val not in self._mapping:
                 self._mapping[val] = next(self._counter)
-        if convertable:
+        if convertible:
             _log.info('Using categorical units to plot a list of strings '
                       'that are all parsable as floats or dates. If these '
                       'strings should be plotted as numbers, cast to the '