diff --git a/phc2sys.8 b/phc2sys.8
index 3a8683e..45cb0e3 100644
--- a/phc2sys.8
+++ b/phc2sys.8
@@ -154,9 +154,9 @@ after the start. The default is 0.0.
 .TP
 .BI \-F " step"
 Specify the step threshold applied only on the first update. It is the maximum
-offset that is corrected by adjusting clock. It's specified in seconds. The
-value of 0.0 disables stepping on start.
-The default is 0.00002 (20 microseconds).
+offset that is corrected by changing the clock frequency. It's specified in
+seconds. The value of 0.0 disables stepping on start. The default is 0.00002
+(20 microseconds).
 .TP
 .BI \-R " update-rate"
 Specify the slave clock update rate when running in the direct synchronization