diff --git a/pandas/core/base.py b/pandas/core/base.py
index aa051c6f5eaef..c331ead8d2fef 100644
--- a/pandas/core/base.py
+++ b/pandas/core/base.py
@@ -114,7 +114,7 @@ def _reset_cache(self, key=None):
 
     def __sizeof__(self):
         """
-        Generates the total memory usage for a object that returns
+        Generates the total memory usage for an object that returns
         either a value or Series of values
         """
         if hasattr(self, 'memory_usage'):