diff --git a/src/NumHask/Array/Dynamic.hs b/src/NumHask/Array/Dynamic.hs
index 51feef1..69db2ee 100644
--- a/src/NumHask/Array/Dynamic.hs
+++ b/src/NumHask/Array/Dynamic.hs
@@ -22,6 +22,10 @@ module NumHask.Array.Dynamic
     unsafeModifyShape,
     unsafeModifyVector,
 
+    -- * Dimensions
+    Dim,
+    Dims,
+
     -- * Conversion
     FromVector (..),
     FromArray (..),
@@ -388,6 +392,12 @@ unsafeModifyShape f (UnsafeArray s v) = UnsafeArray (f s) v
 unsafeModifyVector :: (FromVector u a) => (FromVector v b) => (u -> v) -> Array a -> Array b
 unsafeModifyVector f (UnsafeArray s v) = UnsafeArray s (asVector (f (vectorAs v)))
 
+-- | Representation of an index into a shape (an [Int]). The index is a dimension of the shape.
+type Dim = Int
+
+-- | Representation of indexes into a shape (an [Int]). The indexes are dimensions of the shape.
+type Dims = [Int]
+
 -- | shape of an Array
 --
 -- >>> shape a
@@ -642,7 +652,7 @@ imap f a = zipWith f (indices (shape a)) a
 --
 -- >>> rowWise indexes [1,0] a
 -- UnsafeArray [4] [12,13,14,15]
-rowWise :: ([Int] -> [x] -> Array a -> Array a) -> [x] -> Array a -> Array a
+rowWise :: (Dims -> [x] -> Array a -> Array a) -> [x] -> Array a -> Array a
 rowWise f xs a = f [0..(S.rank xs - 1)] xs a
 
 -- | Apply a function that takes dimensions & parameters and applies a parameter list to the the last dimensions (in reverse). ie
@@ -651,14 +661,14 @@ rowWise f xs a = f [0..(S.rank xs - 1)] xs a
 --
 -- >>> colWise indexes [1,0] a
 -- UnsafeArray [2] [1,13]
-colWise :: ([Int] -> [x] -> Array a -> Array a) -> [x] -> Array a -> Array a
+colWise :: (Dims -> [x] -> Array a -> Array a) -> [x] -> Array a -> Array a
 colWise f xs a = f (List.reverse [(rank a - (S.rank xs)) .. (rank a - 1)]) xs a
 
 -- | Apply a function that takes a dimension and parameter, and folds a (dimension,parameter) list over an array.
 --
 -- >>> dimsWise take [0,2] [1,2] a
 -- UnsafeArray [1,3,2] [0,1,4,5,8,9]
-dimsWise :: (Int -> x -> Array a -> Array a) -> [Int] -> [x] -> Array a -> Array a
+dimsWise :: (Dim -> x -> Array a -> Array a) -> Dims -> [x] -> Array a -> Array a
 dimsWise f ds xs a = foldl' (\a' (d, x) -> f d x a') a (List.zip ds xs)
 
 -- | Take the top-most elements across the specified dimension. Negative values take the bottom-most. No index check is performed.
@@ -680,7 +690,7 @@ dimsWise f ds xs a = foldl' (\a' (d, x) -> f d x a') a (List.zip ds xs)
 --   [19],
 --   [23]]]
 take ::
-  Int ->
+  Dim ->
   Int ->
   Array a ->
   Array a
@@ -706,7 +716,7 @@ take d t a = backpermute dsNew (modifyDim d (\x -> x + bool 0 (d' + t) (t < 0)))
 --   [16,17,18],
 --   [20,21,22]]]
 drop ::
-  Int ->
+  Dim ->
   Int ->
   Array a ->
   Array a
@@ -721,7 +731,7 @@ drop d t a = backpermute dsNew (modifyDim d (\x -> x + bool t 0 (t < 0))) a
 -- [[3,7,11],
 --  [15,19,23]]
 select ::
-  Int ->
+  Dim ->
   Int ->
   Array a ->
   Array a
@@ -739,7 +749,7 @@ select d x a = backpermute (deleteDim d) (insertDim d x) a
 -- >>> D.insert 0 0 (D.toScalar 1) (D.toScalar 2)
 -- UnsafeArray [2] [2,1]
 insert ::
-  Int ->
+  Dim ->
   Int ->
   Array a ->
   Array a ->
@@ -761,7 +771,7 @@ insert d i a b = tabulate (incAt d (shape (asSingleton a))) go
 --   [16,17,18],
 --   [20,21,22]]]
 delete ::
-  Int ->
+  Dim ->
   Int ->
   Array a ->
   Array a
@@ -777,7 +787,7 @@ delete d i a = backpermute (decAt d) (\s -> bool s (incAt d s) (s !! d < i)) (as
 --   [16,17,18,19,0],
 --   [20,21,22,23,0]]]
 append ::
-  Int ->
+  Dim ->
   Array a ->
   Array a ->
   Array a
@@ -793,7 +803,7 @@ append d a b = insert d (getDim d (shape a)) a b
 --   [0,16,17,18,19],
 --   [0,20,21,22,23]]]
 prepend ::
-  Int ->
+  Dim ->
   Array a ->
   Array a ->
   Array a
@@ -808,7 +818,7 @@ prepend d a b = insert d 0 b a
 -- >>> concatenate 0 (toScalar 0) (asArray [1..3])
 -- UnsafeArray [4] [0,1,2,3]
 concatenate ::
-  Int ->
+  Dim ->
   Array a ->
   Array a ->
   Array a
@@ -849,7 +859,7 @@ couple a a' = concatenate 0 (elongate 0 a) (elongate 0 a')
 --   [17,18],
 --   [21,22]]]
 slice ::
-  Int ->
+  Dim ->
   Int ->
   Int ->
   Array a ->
@@ -867,7 +877,7 @@ slice d o l a = backpermute (setDim d l) (modifyDim d (+ o)) a
 --   [5,6,7],
 --   [9,10,11]]]
 takes ::
-  [Int] ->
+  Dims ->
   [Int] ->
   Array a ->
   Array a
@@ -882,7 +892,7 @@ takes ds xs a = backpermute dsNew (List.zipWith (+) start) a
 -- >>> pretty $ drops [0,1,2] [1,2,-3] a
 -- [[[20]]]
 drops ::
-  [Int] ->
+  Dims ->
   [Int] ->
   Array a ->
   Array a
@@ -898,7 +908,7 @@ drops ds xs a = backpermute dsNew (List.zipWith (\d' s' -> bool (d' + s') s' (d'
 -- >>> pretty s
 -- [16,17,18,19]
 indexes ::
-  [Int] ->
+  Dims ->
   [Int] ->
   Array a ->
   Array a
@@ -912,7 +922,7 @@ indexes ds xs a = backpermute (deleteDims ds) (insertDims ds xs) a
 --   [17,18],
 --   [21,22]]]
 slices ::
-  [Int] ->
+  Dims ->
   [Int] ->
   [Int] ->
   Array a ->
@@ -923,14 +933,14 @@ slices ds os ls a = dimsWise (\d (o,l) -> slice d o l) ds (List.zip os ls) a
 --
 -- >>> pretty $ heads [0,2] a
 -- [0,4,8]
-heads :: [Int] -> Array a -> Array a
+heads :: Dims -> Array a -> Array a
 heads ds a = indexes ds (List.replicate (S.rank ds) 0) a
 
 -- | Select the last element along the supplied dimensions
 --
 -- >>> pretty $ lasts [0,2] a
 -- [15,19,23]
-lasts :: [Int] -> Array a -> Array a
+lasts :: Dims -> Array a -> Array a
 lasts ds a = indexes ds lastds a
   where
     lastds = (\i -> shape a !! i - 1) <$> ds
@@ -941,7 +951,7 @@ lasts ds a = indexes ds lastds a
 -- [[[13,14,15],
 --   [17,18,19],
 --   [21,22,23]]]
-tails :: [Int] -> Array a -> Array a
+tails :: Dims -> Array a -> Array a
 tails ds a = slices ds os ls a
   where
     os = List.replicate (S.rank ls) 1
@@ -953,7 +963,7 @@ tails ds a = slices ds os ls a
 -- [[[0,1,2],
 --   [4,5,6],
 --   [8,9,10]]]
-inits :: [Int] -> Array a -> Array a
+inits :: Dims -> Array a -> Array a
 inits ds a = slices ds os ls a
   where
     os = List.replicate (S.rank ls) 0
@@ -967,7 +977,7 @@ inits ds a = slices ds os ls a
 -- >>> pretty $ shape <$> extracts [0] a
 -- [[3,4],[3,4]]
 extracts ::
-  [Int] ->
+  Dims ->
   Array a ->
   Array (Array a)
 extracts ds a = tabulate (getDims ds (shape a)) go
@@ -980,7 +990,7 @@ extracts ds a = tabulate (getDims ds (shape a)) go
 -- >>> pretty $ shape <$> extracts [0] a
 -- [[3,4],[3,4]]
 extractsExcept ::
-  [Int] ->
+  Dims ->
   Array a ->
   Array (Array a)
 extractsExcept ds a = extracts (exclude (rank a) ds) a
@@ -994,7 +1004,7 @@ extractsExcept ds a = extracts (exclude (rank a) ds) a
 --  [48,51,54,57]]
 --
 reduces ::
-  [Int] ->
+  Dims ->
   (Array a -> b) ->
   Array a ->
   Array b
@@ -1007,7 +1017,7 @@ reduces ds f a = fmap f (extracts ds a)
 -- >>> a == j
 -- True
 joins ::
-  [Int] ->
+  Dims ->
   Array (Array a) ->
   Array a
 joins ds a = tabulate (insertDims ds so si) go
@@ -1023,7 +1033,7 @@ joins ds a = tabulate (insertDims ds so si) go
 -- >>> a == j
 -- True
 joinsSafe ::
-  [Int] ->
+  Dims ->
   Array (Array a) ->
   Either NumHaskException (Array a)
 joinsSafe ds a =
@@ -1063,7 +1073,7 @@ allEqual a = case arrayAs a of
 -- | Traverse along specified dimensions.
 traverses ::
   (Applicative f) =>
-  [Int] ->
+  Dims ->
   (a -> f b) ->
   Array a ->
   f (Array b)
@@ -1074,7 +1084,7 @@ traverses ds f a = join <$> traverse (traverse f) (extracts ds a)
 -- >>> shape $ maps [1] transpose a
 -- [4,3,2]
 maps ::
-  [Int] ->
+  Dims ->
   (Array a -> Array b) ->
   Array a ->
   Array b
@@ -1088,7 +1098,7 @@ maps ds f a = joins ds (fmap f (extracts ds a))
 --  [12,13,14,15],
 --  [20,21,22,23]]
 filters ::
-  [Int] ->
+  Dims ->
   (Array a -> Bool) ->
   Array a ->
   Array a
@@ -1104,7 +1114,7 @@ filters ds p a = join (asArray $ V.filter p $ asVector (extracts ds a))
 --   [(16,4),(17,5),(18,6),(19,7)],
 --   [(20,8),(21,9),(22,10),(23,11)]]]
 zips ::
-  [Int] ->
+  Dims ->
   (Array a -> Array b -> Array c) ->
   Array a ->
   Array b ->
@@ -1116,7 +1126,7 @@ zips ds f a b = joins ds (zipWith f (extracts ds a) (extracts ds b))
 -- >>> zipsSafe [0] (zipWith (,)) (asArray [1::Int]) (asArray [1,2::Int])
 -- Left (NumHaskException {errorMessage = "MisMatched zip"})
 zipsSafe ::
-  [Int] ->
+  Dims ->
   (Array a -> Array b -> Array c) ->
   Array a ->
   Array b ->
@@ -1138,7 +1148,7 @@ zipsSafe ds f a b =
 --   [120,21,22,23]]]
 modifies ::
   (Array a -> Array a) ->
-  [Int] ->
+  Dims ->
   [Int] ->
   Array a ->
   Array a
@@ -1151,7 +1161,7 @@ modifies f ds ps a = joins ds $ modify ps f (extracts ds a)
 --   [4,4,4,4]],
 --  [[4,4,4,4],
 --   [4,4,4,4]]]
-diffs :: [Int] -> [Int] -> (Array a -> Array a -> Array b) -> Array a -> Array b
+diffs :: Dims -> [Int] -> (Array a -> Array a -> Array b) -> Array a -> Array b
 diffs ds xs f a = zips ds f (drops ds xs a) (drops ds (fmap P.negate xs) a)
 
 -- | Product two arrays using the supplied binary function.
@@ -1219,7 +1229,7 @@ expandr f a b = tabulate (shape a <> shape b) (\i -> f (index a (List.drop r i))
 --  [32,77]]
 contract ::
   (Array a -> b) ->
-  [Int] ->
+  Dims ->
   Array a ->
   Array b
 contract f xs a = f . diag <$> extractsExcept xs a
@@ -1516,7 +1526,7 @@ rerank r a = unsafeModifyShape (S.rerank r) a
 --  [[3,7,11],
 --   [15,19,23]]]
 reorder ::
-  [Int] ->
+  Dims ->
   Array a ->
   Array a
 reorder ds a = backpermute (`S.reorder` ds) (\s -> insertDims ds s []) a
@@ -1538,7 +1548,7 @@ squeeze a = unsafeModifyShape S.squeeze a
 -- >>> elongate 0 (toScalar 1)
 -- UnsafeArray [1] [1]
 elongate ::
-  Int ->
+  Dim ->
   Array a ->
   Array a
 elongate d a = unsafeModifyShape (insertDim d 1) a
@@ -1563,7 +1573,7 @@ transpose a = backpermute List.reverse List.reverse a
 -- [[0,1,2],
 --  [0,1,2]]
 inflate ::
-  Int ->
+  Dim ->
   Int ->
   Array a ->
   Array a
@@ -1578,7 +1588,7 @@ inflate d n a = backpermute (insertDim d n) (deleteDim d) a
 --  [[12,0,13,0,14,0,15],
 --   [16,0,17,0,18,0,19],
 --   [20,0,21,0,22,0,23]]]
-intercalate:: [Int] -> Array a -> Array a -> Array a
+intercalate:: Dims -> Array a -> Array a -> Array a
 intercalate ds i a = joins ds $ asArray (List.intersperse i (arrayAs (extracts ds a)))
 
 -- | Intersperse an element along dimensions.
@@ -1590,7 +1600,7 @@ intercalate ds i a = joins ds $ asArray (List.intersperse i (arrayAs (extracts d
 --  [[12,0,13,0,14,0,15],
 --   [16,0,17,0,18,0,19],
 --   [20,0,21,0,22,0,23]]]
-intersperse :: [Int] -> a -> Array a -> Array a
+intersperse :: Dims -> a -> Array a -> Array a
 intersperse ds i a = intercalate ds (konst (deleteDims ds (shape a)) i) a
 
 -- | Concatenate and replace dimensions, creating a new dimension at the supplied postion.
@@ -1601,7 +1611,7 @@ intersperse ds i a = intercalate ds (konst (deleteDims ds (shape a)) i) a
 --  [2,6,10,14,18,22],
 --  [3,7,11,15,19,23]]
 concats ::
-  [Int] ->
+  Dims ->
   Int ->
   Array a ->
   Array a
@@ -1620,7 +1630,7 @@ concats ds n a = backpermute concatDims unconcatDims a
 --   [12,13,14,15],
 --   [16,17,18,19]]]
 rotate ::
-  Int ->
+  Dim ->
   Int ->
   Array a ->
   Array a
@@ -1636,7 +1646,7 @@ rotate d r a = backpermute id (modifyDim d (\i -> (r + i) `mod` (shape a !! d)))
 --   [4,5,6,7],
 --   [0,1,2,3]]]
 reverses ::
-  [Int] ->
+  Dims ->
   Array a ->
   Array a
 reverses ds a = backpermute id (reverseIndex ds (shape a)) a
@@ -1651,7 +1661,7 @@ reverses ds a = backpermute id (reverseIndex ds (shape a)) a
 -- UnsafeArray [2,2] [2,3,1,4]
 -- >>> sorts [0,1] (array [2,2] [2,3,1,4])
 -- UnsafeArray [2,2] [1,2,3,4]
-sorts :: (Ord a) => [Int] -> Array a -> Array a
+sorts :: (Ord a) => Dims -> Array a -> Array a
 sorts ds a = joins ds $ unsafeModifyVector sortV (extracts ds a)
 
 -- | The indices into the array if it were sorted by a comparison function along the dimensions supplied.
@@ -1659,14 +1669,14 @@ sorts ds a = joins ds $ unsafeModifyVector sortV (extracts ds a)
 -- >>> import Data.Ord (Down (..))
 -- >>> sortsBy [0] (fmap Down) (array [2,2] [2,3,1,4])
 -- UnsafeArray [2,2] [2,3,1,4]
-sortsBy :: (Ord b) => [Int] -> (Array a -> Array b) -> Array a -> Array a
+sortsBy :: (Ord b) => Dims -> (Array a -> Array b) -> Array a -> Array a
 sortsBy ds c a = joins ds $ unsafeModifyVector (sortByV c) (extracts ds a)
 
 -- | The indices into the array if it were sorted along the dimensions supplied.
 --
 -- >>> orders [0] (array [2,2] [2,3,1,4])
 -- UnsafeArray [2] [1,0]
-orders :: (Ord a) => [Int] -> Array a -> Array Int
+orders :: (Ord a) => Dims -> Array a -> Array Int
 orders ds a = unsafeModifyVector orderV (extracts ds a)
 
 -- | The indices into the array if it were sorted by a comparison function along the dimensions supplied.
@@ -1674,7 +1684,7 @@ orders ds a = unsafeModifyVector orderV (extracts ds a)
 -- >>> import Data.Ord (Down (..))
 -- >>> ordersBy [0] (fmap Down) (array [2,2] [2,3,1,4])
 -- UnsafeArray [2] [0,1]
-ordersBy :: (Ord b) => [Int] -> (Array a -> Array b) -> Array a -> Array Int
+ordersBy :: (Ord b) => Dims -> (Array a -> Array b) -> Array a -> Array Int
 ordersBy ds c a = unsafeModifyVector (orderByV c) (extracts ds a)
 
 -- * transmission
@@ -1687,7 +1697,7 @@ ordersBy ds c a = unsafeModifyVector (orderByV c) (extracts ds a)
 -- [[0,1,2],
 --  [3,4,5],
 --  [0,1,2]]
-telecasts :: [Int] -> [Int] -> (Array a -> Array b -> Array c) -> Array a -> Array b -> Array c
+telecasts :: Dims -> Dims -> (Array a -> Array b -> Array c) -> Array a -> Array b -> Array c
 telecasts dsa dsb f a b = zipWith f (extracts dsa a) (extracts dsb b) & joins dsa
 
 -- | Apply a binary array function to two arrays with matching shapes across the supplied dimensions. Checks shape.
@@ -1696,7 +1706,7 @@ telecasts dsa dsb f a b = zipWith f (extracts dsa a) (extracts dsb b) & joins ds
 -- >>> b = D.array [1] [1]
 -- >>> telecastsSafe [0] [0] (zipWith (+)) a b
 -- Left (NumHaskException {errorMessage = "MisMatched telecasting"})
-telecastsSafe :: [Int] -> [Int] -> (Array a -> Array b -> Array c) -> Array a -> Array b -> Either NumHaskException (Array c)
+telecastsSafe :: Dims -> Dims -> (Array a -> Array b -> Array c) -> Array a -> Array b -> Either NumHaskException (Array c)
 telecastsSafe dsa dsb f a b =
   bool
     (Right $ telecasts dsa dsb f a b)
diff --git a/src/NumHask/Array/Fixed.hs b/src/NumHask/Array/Fixed.hs
index bace549..afff2c7 100644
--- a/src/NumHask/Array/Fixed.hs
+++ b/src/NumHask/Array/Fixed.hs
@@ -25,7 +25,11 @@ module NumHask.Array.Fixed
     unsafeModifyShape,
     unsafeModifyVector,
 
-    -- * Dependent type
+    -- * Dimensions
+    Dim,
+    Dims,
+
+   -- * Dependent type
     SomeArray (..),
     someArray,
 
@@ -464,6 +468,13 @@ unsafeModifyShape a = unsafeArray (asVector a)
 unsafeModifyVector :: (KnownNats s) => (FromVector u a) => (FromVector v b) => (u -> v) -> Array s a -> Array s b
 unsafeModifyVector f a = unsafeArray (asVector (f (vectorAs (asVector a))))
 
+-- | Representation of an index into a shape (a type-level [Nat]). The index is a dimension of the shape.
+type Dim = SNat
+
+-- | Representation of indexes into a shape (a type-level [Nat]). The indexes are dimensions of the shape.
+type Dims = SNats
+
+
 -- | A fixed Array with a hidden shape.
 --
 -- The library design encourages the use of dynamic arrays in preference to dependent-type styles such as this. In particular, no attempt has been made to prove to the compiler that a particular Shape (resulting from any of the supplied functions) exists. Life is short.
diff --git a/src/NumHask/Array/Shape.hs b/src/NumHask/Array/Shape.hs
index 8bc75b2..ea993a5 100644
--- a/src/NumHask/Array/Shape.hs
+++ b/src/NumHask/Array/Shape.hs
@@ -55,10 +55,6 @@ module NumHask.Array.Shape
     Fins (..),
     toFins,
 
-    -- * Dimensions
-    Dim,
-    Dims,
-
     -- operators
     rank,
     Rank,
@@ -345,12 +341,6 @@ instance Show (Fins n) where
 toFins :: forall s. (KnownNats s) => [Int] -> Maybe (Fins s)
 toFins xs = bool Nothing (Just (UnsafeFins xs)) (isFins xs (valuesOf @s))
 
--- | An SNat (a type-level Nat) that represents an index into an SNats (a type-level [Nat]). The index is a dimension of the shape.
-type Dim = SNat
-
--- | An SNats (a type-level [Nat]) that represents indexes into an SNats (a type-level [Nat]). The indexes are dimensions of the shape.
-type Dims = SNats
-
 -- | Number of dimensions
 --
 -- >>> rank @Int [2,3,4]