diff --git a/lasy/laser.py b/lasy/laser.py
index 28db5657..09964cc8 100644
--- a/lasy/laser.py
+++ b/lasy/laser.py
@@ -251,7 +251,7 @@ def propagate(self, distance, **kwargs):
         distance : scalar
             Distance by which the laser pulse should be propagated
 
-        grid : Grid object (optional)
+        grid_out : Grid object (optional)
             Resample the field onto a new grid of different radial size and/or different number
             of radial grid points. Only works for ``'rt'``.
         """