Fix typo in dictionary section
diff --git a/README.md b/README.md
index 8c3f3f0..67f1f11 100644
--- a/README.md
+++ b/README.md
@@ -515,7 +515,7 @@ What is going on here?
   
     > Equality tests between OrderedDict objects are order-sensitive and are implemented as `list(od1.items())==list(od2.items())`. Equality tests between `OrderedDict` objects and other Mapping objects are order-insensitive like regular dictionaries.
 - The reason for this equality is behavior is that it allows `OrderedDict` objects to be directly substituted anywhere a regular dictionary is used.
-- Okay, so why did changing the order affect the lenght of the generated `set` object? The answer is the lack of intransitive equality only. Since sets are "unordered" collections of unique elements, the order in which elements are inserted shouldn't matter. But in this case, it does matter. Let's break it down a bit,
+- Okay, so why did changing the order affect the length of the generated `set` object? The answer is the lack of intransitive equality only. Since sets are "unordered" collections of unique elements, the order in which elements are inserted shouldn't matter. But in this case, it does matter. Let's break it down a bit,
     ```py
     >>> some_set = set()
     >>> some_set.add(dictionary) # these are the mapping objects from the snippets above
