Given a collection of glossary definition pages, automatically creates links in your page and post content for the words in your glossary.
Is smart enough not to create illegal nested links.
Works with php 4 and 5 (check out the FAQ for more info on using it with php 4).
Only tested on WordPress version 2.7.1 (although will most likely work on other versions).
A good example of the glossary in action is at <a href="http://www.alaskaedu.net/2009/02/17/alaska-charter-schools/" rel="nofollow ugc">this page</a>. All of the “charter school” links were added dynamically by the glossary plugin.

Glossary

Given a collection of glossary definition pages, automatically creates links in your page and post content for the words in your glossary.

Parses posts for defined glossary terms and adds links to the static glossary page containing the definition. The plugin also creates a tooltip containing the definition which is displayed when users mouseover the term. Based on <a href="https://wordpress.org/extend/plugins/automatic-glossary/" rel="ugc">automatic-glossary</a>.
The code has been optimised from automatic-glossary and unnecessary code has been stripped to keep the plugin lean. However, support for php 4 has been removed and if you are looking for a php 4 glossary, please do download automatic-glossary (although I believe there is a little extra tweaking required).
The tooltip is created with JavaScript based on the article written by <a href="http://www.leigeber.com/author/michael/" rel="nofollow ugc">Michael Leigeber</a> <a href="http://sixrevisions.com/tutorials/javascript_tutorial/create_lightweight_javascript_tooltip/" rel="nofollow ugc">here</a> and can be customized and styled through the tooltip.css and tooltip.js files.
Users of WordPress versions less than 3.0 should use version 1.1 of this plugin.

TooltipGlossary

Parses posts for defined glossary terms and adds links to the static glossary page containing the definition and a tooltip with the definition.

Glossary vs TooltipGlossary