diff --git a/README.md b/README.md
index 7558e35..6f0d7a3 100644
--- a/README.md
+++ b/README.md
@@ -92,6 +92,7 @@ The `PO` class exposes the following members:
 * `flags`: A dictionary of the string flags. Each flag is mapped to a key with
   value true. For instance, a string with the fuzzy flag set will have
   `item.flags.fuzzy == true`.
+* `msgctxt`: context of the message, an arbitrary string, can be used for disambiguation
 
 
 ## Contributing