Haldaug

<p>This plugin creates a widget that displays excerpts from Wikipedia on the tag pages (the template tag.php). The user can specify multiple languages for the plugin to query using the Wikipeida API. The language that has an article that matches the tag has its article displayed.</p>
<h3>Credits</h3>
<p>This widget is based on the WordPress-Wikipedia-Widget by patlockley: <a href="https://github.com/patlockley/WordPress-Wikipedia-Widget" rel="nofollow ugc">WordPress-Wikipedia-Widget</a></p>


Wikipedia for tag pages

A widget that displays excerpts from Wikipedia articles relevant to the tag on tag-pages. Support for multiple languages.

flashpixx

<p>The plugin is a Wikipedia plugin, for setting links to Wikipedia articles. The language and the description for every link can be set individually.</p>
<h3>Requirements</h3>
<ul>
<li>WordPress 3.2 or newer</li>
<li>PHP 5.3.0 or newer</li>
</ul>
<h3>Shortcode</h3>
<p>Add to your content of a page or article</p>
<pre>[[search tag]]</pre>
<p>Another way for using the Wikipedia call, is to use the additional syntax</p>
<pre>[[ article | view ]]</pre>
<p>creates a link to the article and within the content the view text is shown</p>
<pre>[[ language | article | view ]]</pre>
<p>creates a link to the article with the language and within the content the view text is shown</p>


Reference 2 Wiki

Creates links to Wikipedia with different languages

Wikipedia for tag pages vs Reference 2 Wiki