diff --git a/format_docs/rb.txt b/format_docs/rb.txt
index 2eb1992afb..2912f0e9bd 100644
--- a/format_docs/rb.txt
+++ b/format_docs/rb.txt
@@ -126,7 +126,7 @@ values that the RocketWriter generates:
 
 Encrypted titles have a few more entries (including those listed above):
 
-    ISBN=<ISBN number, including dashes>
+    ISBN=<ISBN, including dashes>
     REVISION=<digits>
     TITLE_LANGUAGE=<en-us>
     PUB_NAME=<Publisher's name>
diff --git a/manual/template_lang.rst b/manual/template_lang.rst
index addad381af..406f98f154 100644
--- a/manual/template_lang.rst
+++ b/manual/template_lang.rst
@@ -27,7 +27,7 @@ You can use all the various metadata fields available in calibre in a template,
 In addition to the column based fields, you also can use::
 
     {formats} - A list of formats available in the calibre library for a book
-    {identifiers:select(isbn)} - The ISBN number of the book
+    {identifiers:select(isbn)} - The ISBN of the book
 
 If a particular book does not have a particular piece of metadata, the field in the template is automatically removed for that book. Consider, for example::
 
diff --git a/src/calibre/gui2/metadata/basic_widgets.py b/src/calibre/gui2/metadata/basic_widgets.py
index 629e6b84b6..f78501fa4e 100644
--- a/src/calibre/gui2/metadata/basic_widgets.py
+++ b/src/calibre/gui2/metadata/basic_widgets.py
@@ -1529,10 +1529,10 @@ class IdentifiersEdit(QLineEdit, ToMetadataMixin):
             col = 'none'
         elif check_isbn(isbn) is not None:
             col = OK_COLOR
-            extra = '\n\n'+_('This ISBN number is valid')
+            extra = '\n\n'+_('This ISBN is valid')
         else:
             col = ERR_COLOR
-            extra = '\n\n' + _('This ISBN number is invalid')
+            extra = '\n\n' + _('This ISBN is invalid')
         self.setToolTip(tt+extra)
         self.setStyleSheet(INDICATOR_SHEET % col)
 
@@ -1611,10 +1611,10 @@ class ISBNDialog(QDialog):  # {{{
             extra = ''
         elif check_isbn(isbn) is not None:
             col = OK_COLOR
-            extra = _('This ISBN number is valid')
+            extra = _('This ISBN is valid')
         else:
             col = ERR_COLOR
-            extra = _('This ISBN number is invalid')
+            extra = _('This ISBN is invalid')
         self.line_edit.setToolTip(extra)
         self.line_edit.setStyleSheet(INDICATOR_SHEET % col)