Most people use the iOS Spotlight as an application launcher, for locating contacts and searching emails and notes. Many might not realise that you can search the web and Wikipedia directly from iOS Spotlight.
Activate Spotlight by swiping down on iOS home screen. Enter the query string that you would like to do a web or Wikipedia search. A list will appear below the search field that list down apps, contacts, emails etc in your iOS device that matches the search string.
Scroll down to the bottom and you will find the options to “Search Web” or “Search Wikipedia”. Tap on your choice and spotlight will launch Safari and search your query string.