diff --git a/meanas/fdmath/__init__.py b/meanas/fdmath/__init__.py
index 0e165e2..0803099 100644
--- a/meanas/fdmath/__init__.py
+++ b/meanas/fdmath/__init__.py
@@ -8,20 +8,20 @@ Fields, Functions, and Operators
 
 Discrete fields are stored in one of two forms:
 
-- The `field_t` form is a multidimensional `numpy.ndarray`
+- The `fdfield_t` form is a multidimensional `numpy.ndarray`
     + For a scalar field, this is just `U[m, n, p]`, where `m`, `n`, and `p` are
       discrete indices referring to positions on the x, y, and z axes respectively.
     + For a vector field, the first index specifies which vector component is accessed:
       `E[:, m, n, p] = [Ex[m, n, p], Ey[m, n, p], Ez[m, n, p]]`.
-- The `vfield_t` form is simply a vectorzied (i.e. 1D) version of the `field_t`,
+- The `vfdfield_t` form is simply a vectorzied (i.e. 1D) version of the `field_t`,
     as obtained by `meanas.fdmath.vectorization.vec` (effectively just `numpy.ravel`)
 
 Operators which act on fields also come in two forms:
     + Python functions, created by the functions in `meanas.fdmath.functional`.
-        The generated functions act on fields in the `field_t` form.
+        The generated functions act on fields in the `fdfield_t` form.
     + Linear operators, usually 2D sparse matrices using `scipy.sparse`, created
         by `meanas.fdmath.operators`. These operators act on vectorized fields in the
-        `vfield_t` form.
+        `vfdfield_t` form.
 
 The operations performed should be equivalent: `functional.op(*args)(E)` should be
 equivalent to `unvec(operators.op(*args) @ vec(E), E.shape[1:])`.
diff --git a/meanas/fdmath/types.py b/meanas/fdmath/types.py
index 6e2fd63..f8719d1 100644
--- a/meanas/fdmath/types.py
+++ b/meanas/fdmath/types.py
@@ -29,12 +29,15 @@ dx_lists_t = List[List[numpy.ndarray]]
 '''
  'dxes' datastructure which contains grid cell width information in the following format:
 
-     [[[dx_e_0, dx_e_1, ...], [dy_e_0, ...], [dz_e_0, ...]],
-      [[dx_h_0, dx_h_1, ...], [dy_h_0, ...], [dz_h_0, ...]]]
+     [[[dx_e[0], dx_e[1], ...], [dy_e[0], ...], [dz_e[0], ...]],
+      [[dx_h[0], dx_h[1], ...], [dy_h[0], ...], [dz_h[0], ...]]]
 
-   where `dx_e_0` is the x-width of the `x=0` cells, as used when calculating dE/dx,
-   and `dy_h_0` is  the y-width of the `y=0` cells, as used when calculating dH/dy, etc.
+   where `dx_e[0]` is the x-width of the `x=0` cells, as used when calculating dE/dx,
+   and `dy_h[0]` is the y-width of the `y=0` cells, as used when calculating dH/dy, etc.
 '''
 
 
 fdfield_updater_t = Callable[[fdfield_t], fdfield_t]
+'''
+ Convenience type for functions which take and return an fdfield_t
+'''