#3214: improve description of duck-typing in glossary.
diff --git a/Doc/glossary.rst b/Doc/glossary.rst
index acd3009..0fe005d 100644
--- a/Doc/glossary.rst
+++ b/Doc/glossary.rst
@@ -154,9 +154,9 @@
object.
duck-typing
- A pythonic programming style which determines an object's type by inspection
- of its method or attribute signature rather than by explicit relationship
- to some type object ("If it looks like a duck and quacks like a duck, it
+ A programming style which does not look at an object's type to determine
+ if it has the right interface; instead, the method or attribute is simply
+ called or used ("If it looks like a duck and quacks like a duck, it
must be a duck.") By emphasizing interfaces rather than specific types,
well-designed code improves its flexibility by allowing polymorphic
substitution. Duck-typing avoids tests using :func:`type` or