How can I choose the definition displayed or create my own definition?

How can I choose the definition displayed or create my own definition?

You can change or create your own definition for custom word lists. These are word lists that you've manually added and created yourself. 

1. Head over to your Class, and click on the Word Work tab. Next, hover your mouse over the custom word list, and click on View/Edit:


2. Hover your mouse over a word, then click on the 3 dots:



3.  Select Definition allows you to choose from a list of already available definitions, while Custom Definition allows you to create your own definition.