diff --git a/src/calibre/ebooks/metadata/book/render.py b/src/calibre/ebooks/metadata/book/render.py
index f910fbe303..3278cce89a 100644
--- a/src/calibre/ebooks/metadata/book/render.py
+++ b/src/calibre/ebooks/metadata/book/render.py
@@ -180,7 +180,7 @@ def mi_to_html(mi, field_list=None, default_author_link=None, use_roman_numbers=
                     st = field
                 series = getattr(mi, field)
                 val = _(
-                    'Book %(sidx)s of <a href="%(href)s" title="%(tt)s">'
+                    '%(sidx)s of <a href="%(href)s" title="%(tt)s">'
                     '<span class="%(cls)s">%(series)s</span></a>') % dict(
                         sidx=fmt_sidx(sidx, use_roman=use_roman_numbers), cls="series_name",
                         series=p(series), href=search_href(st, series),
diff --git a/src/calibre/ebooks/oeb/transforms/jacket.py b/src/calibre/ebooks/oeb/transforms/jacket.py
index bcb9ad437b..1c0a289c67 100644
--- a/src/calibre/ebooks/oeb/transforms/jacket.py
+++ b/src/calibre/ebooks/oeb/transforms/jacket.py
@@ -148,7 +148,7 @@ class Series(unicode):
     def __new__(self, series, series_index):
         series = roman = escape(series or u'')
         if series and series_index is not None:
-            roman = _('Book {1} of <em>{0}</em>').format(
+            roman = _('Number {1} of <em>{0}</em>').format(
                 escape(series), escape(fmt_sidx(series_index, use_roman=True)))
             series = escape(series + ' [%s]'%fmt_sidx(series_index, use_roman=False))
         s = unicode.__new__(self, series)