Chris

This WordPress plugin will allow users to maintain a list of acronyms and abbreviations which can be managed in the WordPress Dashbard. These acronyms will be automatically wrapped in the appropriate HTML markup when found in posts, pages and comments.
The plugin will auto-detect whether the currently active theme uses HTML5, and will output the appropriate HTML acronym or abbreviation element, e.g. <code><acronym title="Hypertext Markup Language">HTML</acronym></code> (or <code><abbr title="Hypertext Markup Language">HTML</abbr></code> for HTML5).
Based on Joel Pan’s excellent Acronyms, which is no longer being actively maintained. The onset of HTML5 and the deprecation of <code><acronym></code> in favour of <code><abbr></code> led me to fork Joel’s plugin and create Acronyms 2.

Acronyms 2

A plugin to automatically mark up known acronyms and abbreviations in posts and comments. Allows users to manage lists of acronyms through the WordPre …

danfinnigan

A plugin to define acronyms in pages, posts and comments using <code><acronym></code> or <code><abbr></code> mark-up. Defined acronyms are underlined, and the definition appears as a tool-tip if the cursor is placed over the acronym. The list of acronyms is managed through an Admin interface.
This plugin is based on Chris Cox’s Acronyms-2, which was itself based on Joel Bennett’s Acronym Replacer plugin (http://www.huddledmasses.org/), ported to Nucleus CMS by Joel Pan as the NP_Acronym plugin and now ported back to WordPress.

Acronym Manager

A plugin to define acronyms in pages, posts and comments site-wide.  Defined acronyms are underlined, and the definition appears as a tool-tip.

Acronyms 2 vs Acronym Manager