diff --git a/securedrop/journalist_templates/_sources_confirmation_final_modal.html b/securedrop/journalist_templates/_sources_confirmation_final_modal.html
index 2753b3c8d4..2e596672c2 100644
--- a/securedrop/journalist_templates/_sources_confirmation_final_modal.html
+++ b/securedrop/journalist_templates/_sources_confirmation_final_modal.html
@@ -2,19 +2,19 @@
   <a href="#close" class="external" aria-label="{{ gettext('Close') }}"></a>
   <dialog open id="delete-confirm-menu-dialog" aria-labelledby="confirm-heading">
     <h2 id="confirm-heading" class="paragraph-spacing">
-      {{ gettext('When the account for a source is deleted:') }}
+      {{ gettext('When the account for a <abr title="user">source</abr>is deleted:') }}
     </h2>
     <ul>
-      <li>{{ gettext('The source will no longer be able to log in with their codename.') }}</li>
+      <li>{{ gettext('The <abr title="user">source</abr> will no longer be able to log in with their <abbr title="user name">codename</abbr>.') }}</li>
       <li>{{ gettext('You will not be able to send them replies.') }}</li>
-      <li>{{ gettext('All files and messages from that source will also be destroyed.') }}</li>
+      <li>{{ gettext('All files and messages from that <abr title="user">source</abr> will also be destroyed.') }}</li>
     </ul>
     <p class="modal-danger-text">{{ gettext('Are you sure this is what you want?') }}</p>
     <div class="btn-row">
       <a href="#close" id="cancel-collections-deletions" title="{{ gettext('Cancel') }}"
         class="btn cancel small">{{ gettext('Cancel') }}</a>
       <button type="submit" id="delete-collections-confirm" name="action" value="delete"
-        class="btn small danger">{{ gettext('Yes, Delete Selected Source Accounts') }}</button>
+        class="btn small danger">{{ gettext('Yes, Delete Selected <abr title="user">Source</abr> Accounts') }}</button>
     </div>
   </dialog>
 </div>
diff --git a/securedrop/journalist_templates/account_new_two_factor_hotp.html b/securedrop/journalist_templates/account_new_two_factor_hotp.html
index c861215e73..22f07f1f3b 100644
--- a/securedrop/journalist_templates/account_new_two_factor_hotp.html
+++ b/securedrop/journalist_templates/account_new_two_factor_hotp.html
@@ -3,7 +3,7 @@
 {% block tab_title %}{{ gettext('Enable YubiKey (OATH-HOTP)') }}{% endblock %}
 
 {% block body %}
-<h1>{{ gettext('Enable YubiKey (OATH-HOTP)') }}</h1>
+<h1>{{ gettext('Enable YubiKey (<abbr title="HMAC-based one-time password algorithm">OATH-HOTP</abbr>)') }}</h1>
 <p>{{ gettext('Once you have configured your YubiKey, enter the 6-digit verification code below:') }}</p>
 <form id="check-token" method="post" action="{{url_for('account.new_two_factor_hotp')}}">
   <input name="csrf_token" type="hidden" value="{{ csrf_token() }}">
diff --git a/securedrop/journalist_templates/admin.html b/securedrop/journalist_templates/admin.html
index fe522bb5d6..78da58ad24 100644
--- a/securedrop/journalist_templates/admin.html
+++ b/securedrop/journalist_templates/admin.html
@@ -85,7 +85,7 @@ <h2 id="users-heading" class="visually-hidden">Users</h2>
 
 <a href="{{ url_for('admin.manage_config') }}" class="btn icon icon-edit section-spacing-inline"
   id="update-instance-config" aria-label="{{ gettext('Update instance configuration') }}">
-  {{ gettext('INSTANCE CONFIG') }}
+  {{ gettext('INSTANCE CONFIGURATION') }}
 </a>
 
 {% endblock %}
diff --git a/securedrop/journalist_templates/col.html b/securedrop/journalist_templates/col.html
index 43169da500..d9d812f011 100644
--- a/securedrop/journalist_templates/col.html
+++ b/securedrop/journalist_templates/col.html
@@ -157,7 +157,7 @@ <h2 id="replies-heading">{{ gettext('Reply') }}</h2>
 Deleting the account for <b>{source}</b> will:
 </p>
 <ul>
-<li>prevent them from logging in with their codename again
+<li>prevent them from logging in with their <abr title="user name">codename</abr>again
 <li>prevent your organization from sending replies
 </ul>
 <p>
diff --git a/securedrop/journalist_templates/config.html b/securedrop/journalist_templates/config.html
index d4b20fcef0..4800fbe598 100644
--- a/securedrop/journalist_templates/config.html
+++ b/securedrop/journalist_templates/config.html
@@ -78,7 +78,7 @@ <h2 id="config-preventuploads">{{ gettext('Submission Preferences') }}</h2>
       <div class="config_form_element">
         {{ submission_preferences_form.reject_codename_messages() }}
         <label
-      for="reject_codename_messages">{{ gettext('Prevent sources from submitting their codename as an initial message.') }}</label>
+      for="reject_codename_messages">{{ gettext('Prevent sources from submitting their <abr title="user name">codename</abr>as an initial message.') }}</label>
       </div>
     <div class="section-spacing">
       <button type="submit" id="submit-submission-preferences" class="icon icon-edit"
diff --git a/securedrop/journalist_templates/js-strings.html b/securedrop/journalist_templates/js-strings.html
index 0aa7cda360..49e633732a 100644
--- a/securedrop/journalist_templates/js-strings.html
+++ b/securedrop/journalist_templates/js-strings.html
@@ -1,6 +1,6 @@
 {# Hack around doing full JS translation support since JS is barely used #}
 <div id="js-strings">
-  <div id="filter-by-codename-placeholder-string" hidden>{{ gettext('Filter by codename') }}</div>
+  <div id="filter-by-codename-placeholder-string" hidden>{{ gettext('Filter by <abr title="user name">codename</abr>') }}</div>
   <div id="select-all-string" hidden>{{ gettext('Select All') }}</div>
   <div id="select-unread-string" hidden>{{ gettext('Select Unread') }}</div>
   <div id="select-none-string" hidden>{{ gettext('Select None') }}</div>
diff --git a/securedrop/source_templates/error.html b/securedrop/source_templates/error.html
index 11911e90e8..b6b663b8ed 100644
--- a/securedrop/source_templates/error.html
+++ b/securedrop/source_templates/error.html
@@ -7,5 +7,5 @@ <h2>{{ gettext('Server error') }}</h2>
 
 <p>{{ gettext('Sorry, the website encountered an error and was unable to complete your request.') }}</p>
 
-<p><a href="{{ url_for('main.login') }}">{{ gettext('Look up a codename...') }}</a></p>
+<p><a href="{{ url_for('main.login') }}">{{ gettext('Look up a <abr title="user name">codename</abr>...') }}</a></p>
 {% endblock %}
diff --git a/securedrop/source_templates/generate.html b/securedrop/source_templates/generate.html
index df3069ff50..6a166b902d 100644
--- a/securedrop/source_templates/generate.html
+++ b/securedrop/source_templates/generate.html
@@ -5,13 +5,13 @@
 {% import 'utils.html' as utils %}
 
 {% block body %}
-<h2>{{ gettext('Get Your Codename') }}</h2>
+<h2>{{ gettext('Get Your <abr title="user name">codename</abr>') }}</h2>
 
 <p id="codename-explanation" class="explanation">
-  {{ gettext('A <em>codename</em> in SecureDrop functions as both your username and your password.') }}
+  {{ gettext('A <em><abr title="user name">codename</abr></em> in SecureDrop functions as both your username and your password.') }}
 </p>
 <p class="explanation">
-  {{ gettext('You will need this codename to log into our SecureDrop later:') }}
+  {{ gettext('You will need this <abr title="user name">codename</abr> to log into our SecureDrop later:') }}
 </p>
 
 {{ utils.codename(codename) }}
diff --git a/securedrop/source_templates/index.html b/securedrop/source_templates/index.html
index c44b1be8e3..bb41d9c5e6 100644
--- a/securedrop/source_templates/index.html
+++ b/securedrop/source_templates/index.html
@@ -70,7 +70,7 @@ <h2 id="first-submission-heading">{{ gettext('First submission') }}</h2>
 
       <section id="return-visit" aria-labelledby="return-visit-heading">
           <h2 id="return-visit-heading">{{ gettext('Return visit') }}</h2>
-          <p>{{ gettext('Already have a codename? Check for replies or submit something new.') }}</p>
+          <p>{{ gettext('Already have a <abr title="user name">codename</abr>? Check for replies or submit something new.') }}</p>
           <a href="{{ url_for('main.login') }}" class="btn secondary"
             aria-label="{{ gettext('Log In Using Your Codename') }}">
             {{ gettext('LOG IN') }}
diff --git a/securedrop/source_templates/lookup.html b/securedrop/source_templates/lookup.html
index 1a20b86f60..f705f2f722 100644
--- a/securedrop/source_templates/lookup.html
+++ b/securedrop/source_templates/lookup.html
@@ -26,9 +26,9 @@ <h2 id="submit-heading">{{ gettext('Submit Messages') }}</h2>
 
   <p>
     {% if allow_document_uploads %}
-    {{ gettext('If you are already familiar with GPG, you can optionally encrypt your files and messages with our <a href="{url}" class="text-link">public key</a> before submission. Files are encrypted as they are received by SecureDrop.').format(url=url_for('info.download_public_key')) }}
+    {{ gettext('If you are already familiar with <abbr title="GNU Privacy Guard">GPG</abbr>, you can optionally encrypt your files and messages with our <a href="{url}" class="text-link">public key</a> before submission. Files are encrypted as they are received by SecureDrop.').format(url=url_for('info.download_public_key')) }}
     {% else %}
-    {{ gettext('If you are already familiar with GPG, you can optionally encrypt your messages with our <a href="{url}" class="text-link">public key</a> before submission.').format(url=url_for('info.download_public_key')) }}
+    {{ gettext('If you are already familiar with <abbr title="GNU Privacy Guard">GPG</abbr>, you can optionally encrypt your messages with our <a href="{url}" class="text-link">public key</a> before submission.').format(url=url_for('info.download_public_key')) }}
     {% endif %}
     {{ gettext('<a href="{url}" class="text-link">Learn more</a>.').format(url=url_for('info.why_download_public_key')) }}
   </p>
@@ -78,7 +78,7 @@ <h2 id="replies-heading">{{ gettext('Read Replies') }}</h2>
   <div id="replies">
     {% if replies %}
     <p class="info">
-      {{ gettext("You have received a reply. To protect your identity in the unlikely event someone learns your codename, please delete all replies when you're done with them. This also lets us know that you are aware of our reply. You can respond by submitting new files and messages above.") }}
+      {{ gettext("You have received a reply. To protect your identity in the unlikely event someone learns your <abr title="user name">codename</abr>, please delete all replies when you're done with them. This also lets us know that you are aware of our reply. You can respond by submitting new files and messages above.") }}
     </p>
     {% for reply in replies %}
     {%- set timestamp = utils.relative_time(reply.date) -%}
diff --git a/securedrop/source_templates/notfound.html b/securedrop/source_templates/notfound.html
index cb6c95837a..ec4b2e4c1f 100644
--- a/securedrop/source_templates/notfound.html
+++ b/securedrop/source_templates/notfound.html
@@ -7,5 +7,5 @@ <h2>{{ gettext('Page not found') }}</h2>
 
 <p id="page-not-found">{{ gettext("Sorry, we couldn't locate what you requested.") }}</p>
 
-<p><a href="{{ url_for('main.login') }}">{{ gettext('Look up a codename...') }}</a></p>
+<p><a href="{{ url_for('main.login') }}">{{ gettext('Look up a <abr title="user name">codename</abr>...') }}</a></p>
 {% endblock %}
diff --git a/securedrop/source_templates/utils.html b/securedrop/source_templates/utils.html
index 6612138e04..f5a47808b0 100644
--- a/securedrop/source_templates/utils.html
+++ b/securedrop/source_templates/utils.html
@@ -6,21 +6,21 @@
 {%- macro codename(codename, new=False) -%}
 {% if new %}
 <section aria-labelledby="codename-reminder">
-  <p id="codename-reminder">{{ gettext('Remember, your codename is:') }}</p>
+  <p id="codename-reminder">{{ gettext('Remember, your <abbr title="user name">codename</abbr> is:') }}</p>
 {% else %}
 <section aria-labelledby="codename-heading">
-  <h2 id="codename-heading" hidden>{{ gettext('Codename') }}</h2>
+  <h2 id="codename-heading" hidden>{{ gettext('<abbr title="user name">Codename</abbr>') }}</h2>
 {% endif %}
 
   <input id="codename-show-checkbox" type="checkbox" role="button"{% if not new %} checked {% endif -%}
     aria-label="{{ gettext('Reveal Codename') }}" aria-controls="codename">
 
   <mark id="codename" lang="en-US" dir="ltr"{% if not new %}
-    aria-describedby="codename-instructions codename-explanation"{% endif %}><span>{{ codename }}</span></mark>
+    aria-describedby="codename-instructions codename-explanation"{% endif %}><span>{{ <abbr title="user name">codename</abbr> }}</span></mark>
 
   <label for="codename-show-checkbox" id="codename-show"
     aria-hidden="true">
-      {{ gettext('Show Codename') }}
+      {{ gettext('Show <abbr title="user name">Codename</abbr>') }}
   </label>
 
 </section>
diff --git a/securedrop/source_templates/why-public-key.html b/securedrop/source_templates/why-public-key.html
index 3c4014b3c2..6dc86a3f03 100644
--- a/securedrop/source_templates/why-public-key.html
+++ b/securedrop/source_templates/why-public-key.html
@@ -6,12 +6,12 @@
 <h2>{{ gettext("Why download the team's public key?") }}</h2>
 <p>{{ gettext("SecureDrop encrypts files and messages after they are submitted. Encrypting messages and files before submission can provide an extra layer of security before your data reaches the SecureDrop server.") }}
 </p>
-<p>{{ gettext("If you are already familiar with the GPG encryption software, you may wish to encrypt your submissions yourself. To do so:") }}
+<p>{{ gettext("If you are already familiar with the <abbr title="GNU Privacy Guard">GPG</abbr> encryption software, you may wish to encrypt your submissions yourself. To do so:") }}
 <ol>
     <li>{{ gettext('<a href="{url}">Download</a> the public key. It will be saved to a file called:
         <p><code>{submission_key_fpr_filename}</code></p>').format(url=url_for('info.download_public_key'), submission_key_fpr_filename=submission_key_fpr + '.asc')|safe }}
     </li>
-    <li>{{ gettext('Import it into your GPG keyring.') }}
+    <li>{{ gettext('Import it into your <abbr title="GNU Privacy Guard">GPG</abbr> keyring.') }}
         <ul>
             <li>{{ gettext('If you are using <a href="{url}">Tails</a>, you can double-click the <code>.asc</code> file you just downloaded and it will be automatically imported to your keyring.').format(url='https://tails.boum.org') }}
             </li>