diff --git a/fowd/operators.py b/fowd/operators.py
index 1c2a406..6cb181e 100644
--- a/fowd/operators.py
+++ b/fowd/operators.py
@@ -352,7 +352,7 @@ def compute_nth_moment(frequencies, wave_spectral_density, n):
 
 
 def compute_mean_wave_period_spectral(zeroth_moment, frequencies, wave_spectral_density):
-    """Compute mean wave period from wave spectral density."""
+    """Compute mean zero-crossing period from wave spectral density."""
     second_moment = compute_nth_moment(frequencies, wave_spectral_density, 2)
     return np.sqrt(zeroth_moment / second_moment)
 
diff --git a/fowd/output.py b/fowd/output.py
index 7cc4ff2..ec222ab 100644
--- a/fowd/output.py
+++ b/fowd/output.py
@@ -260,7 +260,7 @@
             dims=('wave_id_local',),
             dtype='float32',
             attrs=dict(
-                long_name='Mean wave period estimated from spectral density spectrum',
+                long_name='Mean zero-crossing period estimated from spectral density spectrum',
                 units='seconds',
             )
         ),