[bearmode]

The use case here is to look up a word whilst reading a book, not to look up words that are already on your phone screen. If you see a word you don't recognise, you write it into a note and it gives you the definition instantly

[thirdsun]

Pro-tip: Now you could also use iOS' camera app to recognize the text, select it and look it up. I'm not sure if it's faster than the note route but the option is there.