diff --git a/skimage/measure/blocks.py b/skimage/measure/blocks.py
index 0e45cde2..abeef10f 100644
--- a/skimage/measure/blocks.py
+++ b/skimage/measure/blocks.py
@@ -3,7 +3,7 @@ from ..util.shape import view_as_blocks, _pad_asymmetric_zeros
 
 
 def _block_func(image, factors, func):
-    """Down-sample image by integer factors.
+    """Down-sample image by applying function to local blocks.
 
     Parameters
     ----------