diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -71,3 +71,5 @@
 + Added `nicify` form `Text.Nicify`
 + Upgraded dependency `hydrogen-version` form `>=1.2` to `>=1.3`
 
+## v0.12
++ Added `Default`
diff --git a/hydrogen-prelude.cabal b/hydrogen-prelude.cabal
--- a/hydrogen-prelude.cabal
+++ b/hydrogen-prelude.cabal
@@ -1,5 +1,5 @@
 name:                 hydrogen-prelude
-version:              0.11
+version:              0.12
 homepage:             http://scravy.de/hydrogen-prelude/
 synopsis:             Hydrogen Prelude
 license:              MIT
diff --git a/src/Hydrogen/Prelude.hs b/src/Hydrogen/Prelude.hs
--- a/src/Hydrogen/Prelude.hs
+++ b/src/Hydrogen/Prelude.hs
@@ -60,6 +60,7 @@
   , TMap (..)
   , Has (..)
   , Container (..)
+  , Default (..)
   , __
   ) where
 
@@ -238,14 +239,14 @@
     -> [a] -- ^ The list.
     -> a
 -- ^ Returns the head of the list or the default value.
-safeHead def = \case
+safeHead default_ = \case
     x : _ -> x
-    _     -> def
+    _     -> default_
 
 safeHeadAndTail :: a -> [a] -> (a, [a])
-safeHeadAndTail def = \case
+safeHeadAndTail default_ = \case
     x : xs -> (x, xs)
-    _ -> (def, [])
+    _ -> (default_, [])
 
 safeHeadAndTail2 :: a -> a -> [a] -> (a, a, [a])
 safeHeadAndTail2 d1 d2 = \case
@@ -403,3 +404,6 @@
     (?) = flip MultiMap.member
 
 
+class Default a where
+
+    def :: a