diff --git a/docs/source/input.rst b/docs/source/input.rst
index 9a72c748..de5e3b9e 100644
--- a/docs/source/input.rst
+++ b/docs/source/input.rst
@@ -892,12 +892,12 @@ Allows you to control the number of cells of PML that are used on the six sides
 
     #pml_cells: i1 [i2 i3 i4 i5 i6]
 
-* ``i1`` is the number of cells of PML to use on all sides of the model domain, or ``i1`` is the number of cells of PML to use on the side of the model domain in the negative x-axis direction.
-* ``i2`` is the number of cells of PML to use on the side of the model domain in the negative y-axis direction.
-* ``i3`` is the number of cells of PML to use on the side of the model domain in the negative z-axis direction.
-* ``i4`` is the number of cells of PML to use on the side of the model domain in the positive x-axis direction.
-* ``i5`` is the number of cells of PML to use on the side of the model domain in the positive y-axis direction.
-* ``i6`` is the number of cells of PML to use on the side of the model domain in the positive z-axis direction.
+* ``i1`` is the number of cells of PML to use on all sides of the model domain (can be set to zero to completely switch off the PML), or ``i1`` is the number of cells of PML to use on the face of the model domain nearest the origin of the x-axis (xminus).
+* ``i2`` is the number of cells of PML to use on the face of the model domain nearest the origin of the y-axis (yminus).
+* ``i3`` is the number of cells of PML to use on the face of the model domain nearest the origin of the z-axis (zminus).
+* ``i4`` is the number of cells of PML to use on the face of the model domain furthest from the origin of the x-axis (xplus).
+* ``i5`` is the number of cells of PML to use on the face of the model domain furthest from the origin of the y-axis (yplus).
+* ``i6`` is the number of cells of PML to use on the face of the model domain furthest from the origin of the z-axis (zplus).
 * ``i1 i2 i3 i4 i5 i6`` may be set to zero to turn off the PML on a specific side of the model domain.
 
 For example to use a PML with 20 cells (thicker than the default 10 cells) on only the z-axis sides of the domain use: