GrayStud.io

Easy Glossary plugin helps you create a glossary of terms and definitions, automatically link terms in your content, display optional tooltips, and render an A–Z index. It includes a Settings page to customize behavior.

Easy Glossary

A lightweight, flexible glossary plugin that auto-links terms, shows tooltips, and provides an index shortcode.

Haris Zulfiqar

WordPress tooltip plugins lets you add tooltips to plain text and links on your post and pages.
It offers a tinyMCE shortcode GUI which will guide you through the entire process of a tooltip.
This plugin uses jQuery tipTip authored by Drew Wilson http://code.drewwilson.com/entry/tiptip-jquery-plugin.
You can also add tooltips manually by following the pattern below:
<pre><code>[tooltip content="This will show in a tooltip" url="This will make tooltip a link"]Hover over me for tooltip[/tooltip]
</code></pre>
Url is optional. If URL is added, it will render a link otherwise it will be a plain text.

WordPress Tooltip

WordPress tooltip lets you add tooltips to content on your posts and pages.

Easy Glossary vs WordPress Tooltip