The Wikipedia Mobile app (free) today received a major update to version 5.0 for iOS, adding support for 3D Touch on the iPhone 6s and 6s Plus as well as an improved search that not only finds articles in any Wikipedia-supported language, but takes advantage of Spotlight search as well.
If, like me, you like to just see what's out there in Wikipedia, the feed now tailors content to your interests, surroundings (through Location Services), and the daily featured articles and images. As seen in the screenshot above, a deep touch on the app icon now displays a mini-menu of choices. If you've only partially read an article, an additional choice offers to bring you back to it.
Likewise, Spotlight search now displays pertinent articles as results. It's a great way to search for just about anything, and coupled with the microphone button in the Spotlight search field, just about any topic you can think of can return a Wikipedia response.