diff --git a/koha-tmpl/opac-tmpl/bootstrap/en/modules/opac-auth.tt b/koha-tmpl/opac-tmpl/bootstrap/en/modules/opac-auth.tt
index a82b079e03..9ce6ff7d1a 100644
--- a/koha-tmpl/opac-tmpl/bootstrap/en/modules/opac-auth.tt
+++ b/koha-tmpl/opac-tmpl/bootstrap/en/modules/opac-auth.tt
@@ -69,7 +69,7 @@
                                     <!-- This is what is displayed if cas login has failed -->
                                     <p>Sorry, the CAS login also failed, if you have a local login you may use that below.</p>
                                     [% ELSE %]
-                                    If you have a <acronym title="Central Authentication Service">CAS</acronym> account, you may use that below.
+                                    If you have a <abbr title="Central Authentication Service">CAS</abbr> account, you may use that below.
                                     [% END %]
                                     [% ELSE %]
                                     If you have a local account, you may use that below.
@@ -84,7 +84,7 @@
                                 [% END %]
                                 [% IF ( casAuthentication ) %]
                                 <h4>CAS login</h4>
-                                <p>If you do not have a Shibboleth account, but you do have a <acronym title="Central Authentication Service">CAS</acronym> account,
+                                <p>If you do not have a Shibboleth account, but you do have a <abbr title="Central Authentication Service">CAS</abbr> account,
                                 [% ELSE %]
                                 <h4>Local login</h4>
                                 <p>If you do not have a Shibboleth account, but you do have a local login, then you may login below:</p>
@@ -114,7 +114,7 @@
                                     <p>Sorry, the CAS login failed.</p>
                                 [% END %]
 
-                                <p>If you have a <acronym title="Central Authentication Service">CAS</acronym> account,
+                                <p>If you have a <abbr title="Central Authentication Service">CAS</abbr> account,
                                 [% IF ( casServerUrl ) %]
                                     please <a href="[% casServerUrl %]">click here to login</a>.<p>
                                 [% END %]