diff --git a/sumpy/expansion/pde.py b/sumpy/expansion/pde.py
index 308be6a013d8401a587011bd86de9f22855666b0..e0b0b7c83411d694b0aacd2cf6101732f40f02f0 100644
--- a/sumpy/expansion/pde.py
+++ b/sumpy/expansion/pde.py
@@ -27,7 +27,7 @@ from sumpy.tools import add_mi
 
 class PDE(object):
     r"""
-    Represents a iscalar PDEs of dimension `dim`. It is represented by a
+    Represents a scalar, constant-coefficient PDE of dimension `dim`. It is represented by a
     dictionary. The dictionary maps a multi-index given as a tuple
     to the coefficient. This object is immutable.
     """