Proper name for the iv thing.
diff --git a/cryptography/hazmat/primitives/interfaces.py b/cryptography/hazmat/primitives/interfaces.py
index d6a05c1..d3962a2 100644
--- a/cryptography/hazmat/primitives/interfaces.py
+++ b/cryptography/hazmat/primitives/interfaces.py
@@ -27,7 +27,7 @@
 
 class ModeWithInitializationVector(six.with_metaclass(abc.ABCMeta)):
     @abc.abstractproperty
-    def iv(self):
+    def initialization_vector(self):
         """
         The value of the initialization vector for this mode.
         """