diff --git a/source/Input_Output.rst b/source/Input_Output.rst
index cd8c19f63ff56954cf8a2179173a86540eb7e9c5..bd4ea54ab402c5c5460fe589373dd64c0cfd4014 100644
--- a/source/Input_Output.rst
+++ b/source/Input_Output.rst
@@ -32,7 +32,7 @@ Exercise
 --------
 
 Write a function which take the path of a file in rebase format
-and return in a dictionnary the collection of the enzyme contains in the file.
+and return in a dictionary the collection of the enzyme contains in the file.
 The sequence of the binding site must be cleaned up.
 
 use the file :download:`rebase_light.txt <_static/data/rebase_light.txt>` to test your code.