diff --git a/definitions/grib2/template.4.30.def b/definitions/grib2/template.4.30.def
index a8b50b976..afb3ae3cd 100644
--- a/definitions/grib2/template.4.30.def
+++ b/definitions/grib2/template.4.30.def
@@ -1,6 +1,6 @@
 # Copyright 2005-2019 ECMWF.
 
-# For grib2 to grib1 convertion
+# For grib2 to grib1 conversion
 constant dataRepresentationType = 90;
 
 # TEMPLATE 4.30, Satellite Product
diff --git a/definitions/grib2/template.4.31.def b/definitions/grib2/template.4.31.def
index c846d7236..0fe7dacb9 100644
--- a/definitions/grib2/template.4.31.def
+++ b/definitions/grib2/template.4.31.def
@@ -1,6 +1,6 @@
 # Copyright 2005-2019 ECMWF.
 
-# For grib2 to grib1 convertion
+# For grib2 to grib1 conversion
 constant dataRepresentationType = 90;
 
 # TEMPLATE 4.31, Satellite Product
diff --git a/definitions/grib2/template.4.311.def b/definitions/grib2/template.4.311.def
index 03066cdc1..85566fa63 100644
--- a/definitions/grib2/template.4.311.def
+++ b/definitions/grib2/template.4.311.def
@@ -1,6 +1,6 @@
 # Copyright 2005-2019 ECMWF.
 
-# For grib2 to grib1 convertion
+# For grib2 to grib1 conversion
 constant dataRepresentationType = 90;
 
 # TEMPLATE 4.311, Satellite Product Auxiliary Information
diff --git a/definitions/grib2/template.4.32.def b/definitions/grib2/template.4.32.def
index 04e901256..896eb5fc2 100644
--- a/definitions/grib2/template.4.32.def
+++ b/definitions/grib2/template.4.32.def
@@ -1,6 +1,6 @@
 # Copyright 2005-2019 ECMWF.
 
-# For grib2 to grib1 convertion
+# For grib2 to grib1 conversion
 constant dataRepresentationType = 90;
 
 # TEMPLATE 4.32, Analysis or forecast at a horizontal level or in a horizontal layer at a point in time for simulated (synthetic) satellite data
diff --git a/definitions/grib2/template.4.35.def b/definitions/grib2/template.4.35.def
index b77f5f6ea..de7ede3d3 100644
--- a/definitions/grib2/template.4.35.def
+++ b/definitions/grib2/template.4.35.def
@@ -1,6 +1,6 @@
 # Copyright 2005-2019 ECMWF.
 
-# For grib2 to grib1 convertion
+# For grib2 to grib1 conversion
 constant dataRepresentationType = 90;
 
 # TEMPLATE 4.35, satellite product with or without associated quality values