diff --git a/modbus/ascii/mbascii.c b/modbus/ascii/mbascii.c
index 2394ecca5..3540628ad 100644
--- a/modbus/ascii/mbascii.c
+++ b/modbus/ascii/mbascii.c
@@ -61,7 +61,7 @@
 #define MB_SER_PDU_PDU_OFF    1     /* Offset of Modbus-PDU in Ser-PDU. */
 
 /****************************************************************************
- * Private Type Definitions
+ * Private Typess
  ****************************************************************************/
 
 typedef enum
diff --git a/modbus/rtu/mbrtu.c b/modbus/rtu/mbrtu.c
index cc6b1088e..0f8262d4f 100644
--- a/modbus/rtu/mbrtu.c
+++ b/modbus/rtu/mbrtu.c
@@ -57,7 +57,7 @@
 #define MB_SER_PDU_PDU_OFF      1    /* Offset of Modbus-PDU in Ser-PDU. */
 
 /****************************************************************************
- * Private Type Definitions
+ * Private Typess
  ****************************************************************************/
 
 typedef enum
diff --git a/modbus/rtu/mbrtu_m.c b/modbus/rtu/mbrtu_m.c
index 858274729..ed8e62488 100644
--- a/modbus/rtu/mbrtu_m.c
+++ b/modbus/rtu/mbrtu_m.c
@@ -64,7 +64,7 @@
 #define MB_SER_PDU_PDU_OFF      1     /* Offset of Modbus-PDU in Ser-PDU. */
 
 /****************************************************************************
- * Private Type Definitions
+ * Private Typess
  ****************************************************************************/
 
 typedef enum