diff --git a/libraries/AP_Mount/AP_Mount.cpp b/libraries/AP_Mount/AP_Mount.cpp
index b6e7543ec0..f5802d6572 100644
--- a/libraries/AP_Mount/AP_Mount.cpp
+++ b/libraries/AP_Mount/AP_Mount.cpp
@@ -249,7 +249,7 @@ void AP_Mount::set_mode(uint8_t instance, enum MAV_MOUNT_MODE mode)
     backend->set_mode(mode);
 }
 
-// set yaw_lock.  If true, the gimbal's yaw target is maintained in earth-frame meaning it will lock onto an earth-frame heading (e.g. North)
+// set yaw_lock used in RC_TARGETING mode.  If true, the gimbal's yaw target is maintained in earth-frame meaning it will lock onto an earth-frame heading (e.g. North)
 // If false (aka "follow") the gimbal's yaw is maintained in body-frame meaning it will rotate with the vehicle
 void AP_Mount::set_yaw_lock(uint8_t instance, bool yaw_lock)
 {
diff --git a/libraries/AP_Mount/AP_Mount.h b/libraries/AP_Mount/AP_Mount.h
index 3763a4f822..7d761f53f8 100644
--- a/libraries/AP_Mount/AP_Mount.h
+++ b/libraries/AP_Mount/AP_Mount.h
@@ -151,7 +151,7 @@ public:
     void set_mode_to_default() { set_mode_to_default(_primary); }
     void set_mode_to_default(uint8_t instance);
 
-    // set yaw_lock.  If true, the gimbal's yaw target is maintained in earth-frame meaning it will lock onto an earth-frame heading (e.g. North)
+    // set yaw_lock used in RC_TARGETING mode.  If true, the gimbal's yaw target is maintained in earth-frame meaning it will lock onto an earth-frame heading (e.g. North)
     // If false (aka "follow") the gimbal's yaw is maintained in body-frame meaning it will rotate with the vehicle
     void set_yaw_lock(bool yaw_lock) { set_yaw_lock(_primary, yaw_lock); }
     void set_yaw_lock(uint8_t instance, bool yaw_lock);
diff --git a/libraries/AP_Mount/AP_Mount_Backend.h b/libraries/AP_Mount/AP_Mount_Backend.h
index 50605fa711..f64bde9ec6 100644
--- a/libraries/AP_Mount/AP_Mount_Backend.h
+++ b/libraries/AP_Mount/AP_Mount_Backend.h
@@ -79,7 +79,7 @@ public:
     // set mount's mode
     bool set_mode(enum MAV_MOUNT_MODE mode);
 
-    // set yaw_lock.  If true, the gimbal's yaw target is maintained in earth-frame meaning it will lock onto an earth-frame heading (e.g. North)
+    // set yaw_lock used in RC_TARGETING mode.  If true, the gimbal's yaw target is maintained in earth-frame meaning it will lock onto an earth-frame heading (e.g. North)
     // If false (aka "follow") the gimbal's yaw is maintained in body-frame meaning it will rotate with the vehicle
     void set_yaw_lock(bool yaw_lock) { _yaw_lock = yaw_lock; }
 
@@ -289,7 +289,7 @@ protected:
     uint8_t     _instance;  // this instance's number
 
     MAV_MOUNT_MODE  _mode;          // current mode (see MAV_MOUNT_MODE enum)
-    bool _yaw_lock;                 // True if the gimbal's yaw target is maintained in earth-frame, if false (aka "follow") it is maintained in body-frame
+    bool _yaw_lock;                 // yaw_lock used in RC_TARGETING mode. True if the gimbal's yaw target is maintained in earth-frame, if false (aka "follow") it is maintained in body-frame
 
     // structure for MAVLink Targeting angle and rate targets
     struct {