Just realized that the definition of a word can be seen by clicking in it, by accident. Would be nice to have a chevron or other indicator to show people that this is an option.
Even better would be to have a setting to show the definition by default.
It does mention the tapping in the very first introductory message that appears, but I also know how easy it is to skip over that.
I'm not overly crazy about showing them by default - some people will want to use this as a way to see the word and then try and recall the meaning. Chevrons, maybe, but not sure if that's going to jump out any more than the message at the top of the game.