Remove 'Say Define' (#122)
Fix for idomatic (and correct) English.
diff --git a/README.md b/README.md
index a7985fa..6c22c30 100644
--- a/README.md
+++ b/README.md
@@ -15,7 +15,7 @@
Collections in Dart have no inherent equality. Two sets are not equal, even
if they contain exactly the same objects as elements.
-The `Equality` interface provides a way to say define such an equality. In this
+The `Equality` interface provides a way to define such an equality. In this
case, for example, `const SetEquality(const IdentityEquality())` is an equality
that considers two sets equal exactly if they contain identical elements.
