When I updated to iOS 11 one of the first things I noticed was that search was broken. I would search for “Ama” and iOS would find Amazon Music but not the Amazon app. I could also search for “Shop” and it couldn’t find the Shopkick app. In these examples, they’d only show if I typed the full app name. Turns out this is a feature.
In iOS 10 Spotlight Search was a section under General in settings. Here you could tell Spotlight not to show results from within apps. So if you disable Amazon, it will still show the Amazon app, but not results from within Amazon.
In iOS 11 Spotlight was combined with Siri in their own settings page. Now, if you disable Amazon, you’ll disable results from within the Amazon app from showing up but also the Amazon app unless you type the whole name. iOS 11 also moved over any settings from iOS 10 so apps just seemed to disappear from search.
The fix is easy, just enable the apps in Siri & Search. However, you not only make the apps show up in search again, but you also are enabling show results from within those apps. Whereas this isn’t a big deal for the Amazon app but for apps like Mail and Safari, you either get the app and all their contents in Spotlight Search, or you get neither.
Now you know.