When you're in Google Docs and want to check the definition of a word, all you need to do is type the word (or select an existing one) and perform a quick keyboard shortcut. For Windows users, that shortcut is Control+Shift+Y. For Mac users, it's Command+Shift+Y.
That'll bring up the definition and provide you with the ability to look up more words if you like. It's simple and can be a really useful tool when you're writing.
For a demonstration, check out the video above.