diff --git a/Data/Foldable/Unicode.hs b/Data/Foldable/Unicode.hs
--- a/Data/Foldable/Unicode.hs
+++ b/Data/Foldable/Unicode.hs
@@ -17,6 +17,7 @@
 -- from base:
 import Data.Bool     ( Bool )
 import Data.Eq       ( Eq )
+import Data.Function ( flip )
 import Data.Foldable ( Foldable, elem, notElem )
 
 
@@ -25,14 +26,16 @@
 -------------------------------------------------------------------------------
 
 infix  4 ∈
+infix  4 ∋
 infix  4 ∉
+infix  4 ∌
 
 
 -------------------------------------------------------------------------------
 -- Symbols
 -------------------------------------------------------------------------------
 
-{- |
+{-|
 (∈) = 'elem'
 
 U+2208, ELEMENT OF
@@ -40,10 +43,26 @@
 (∈) ∷ (Foldable t, Eq α) ⇒ α → t α → Bool
 (∈) = elem
 
-{- |
+{-|
+(∋) = 'flip' (∈)
+
+U+220B, CONTAINS AS MEMBER
+-}
+(∋) ∷ (Foldable t, Eq α) ⇒ t α → α → Bool
+(∋) = flip (∈)
+
+{-|
 (∉) = 'notElem'
 
 U+2209, NOT AN ELEMENT OF
 -}
 (∉) ∷ (Foldable t, Eq α) ⇒ α → t α → Bool
 (∉) = notElem
+
+{-|
+(∌) = 'flip' (∉)
+
+U+220C, DOES NOT CONTAIN AS MEMBER
+-}
+(∌) ∷ (Foldable t, Eq α) ⇒ t α → α → Bool
+(∌) = flip (∉)
diff --git a/Data/List/Unicode.hs b/Data/List/Unicode.hs
--- a/Data/List/Unicode.hs
+++ b/Data/List/Unicode.hs
@@ -7,7 +7,11 @@
 Maintainer : Roel van Dijk <vandijk.roel@gmail.com>
 -}
 
-module Data.List.Unicode ( (⧺), (∈), (∉), (∪), (∩) ) where
+module Data.List.Unicode
+    ( (⧺)
+    , (∈), (∋), (∉), (∌)
+    , (∪), (∖), (∆), (∩)
+    ) where
 
 
 -------------------------------------------------------------------------------
@@ -15,9 +19,10 @@
 -------------------------------------------------------------------------------
 
 -- from base:
-import Data.Bool ( Bool )
-import Data.Eq   ( Eq )
-import Data.List ( (++), elem, notElem, union, intersect )
+import Data.Bool     ( Bool )
+import Data.Eq       ( Eq )
+import Data.Function ( flip )
+import Data.List     ( (++), elem, notElem, union, (\\), intersect )
 
 
 -------------------------------------------------------------------------------
@@ -25,8 +30,14 @@
 -------------------------------------------------------------------------------
 
 infix  4 ∈
+infix  4 ∋
 infix  4 ∉
+infix  4 ∌
 infixr 5 ⧺
+infixl 6 ∪
+infixr 6 ∩
+infixl 9 ∖
+infixl 9 ∆
 
 
 -------------------------------------------------------------------------------
@@ -50,6 +61,14 @@
 (∈) = elem
 
 {-|
+(&#x220B;) = 'flip' (&#x2208;)
+
+U+220B, CONTAINS AS MEMBER
+-}
+(∋) ∷ Eq α ⇒ [α] → α → Bool
+(∋) = flip (∈)
+
+{-|
 (&#x2209;) = 'notElem'
 
 U+2209, NOT AN ELEMENT OF
@@ -58,12 +77,38 @@
 (∉) = notElem
 
 {-|
+(&#x220C;) = 'flip' (&#x2209;)
+
+U+220C, DOES NOT CONTAIN AS MEMBER
+-}
+(∌) ∷ Eq α ⇒ [α] → α → Bool
+(∌) = flip (∉)
+
+{-|
 (&#x222A;) = 'union'
 
 U+222A, UNION
 -}
 (∪) ∷ Eq α ⇒ [α] → [α] → [α]
 (∪) = union
+
+{-|
+(&#x2216;) = ('\\')
+
+U+2216, SET MINUS
+-}
+(∖) ∷ Eq α ⇒ [α] → [α] → [α]
+(∖) = (\\)
+
+{-|
+Symmetric difference
+
+a &#x2206; b = (a &#x2216; b) &#x222A; (b &#x2216; a)
+
+U+2206, INCREMENT
+-}
+(∆) ∷ Eq α ⇒ [α] → [α] → [α]
+a ∆ b = (a ∖ b) ∪ (b ∖ a)
 
 {-|
 (&#x2229;) = 'intersect'
diff --git a/base-unicode-symbols.cabal b/base-unicode-symbols.cabal
--- a/base-unicode-symbols.cabal
+++ b/base-unicode-symbols.cabal
@@ -1,5 +1,5 @@
 name:          base-unicode-symbols
-version:       0.1.4
+version:       0.2
 cabal-version: >=1.6
 build-type:    Simple
 stability:     provisional