Author: Chris Koerner
This is a simple Flashlight plugin that allows you to search the English Wikipedia right from Yosemite's Spotlight interface.
To use this, first make sure you've installed Flashlight.
Then, download the zip file.
Place the wikipedia.bundle in the following directory
~/Library/FlashlightPlugins
Start Flashlight and enable the plugin under Featured and Search categories.
The syntax is "wiki query string"