This question could be asked to an entry-level candidate to know if they have a clear understanding of UX and other streams like UI, IA, etc. Many designers confuse visual design with UX. Some are just tool experts who know to operate photoshop and illustrator etc.

This question will help them to know if you have a clear understanding of UX and the streams around it and its connections. Some even have a philosophy of their own. For me, UX is about taking me out of me and thinking like someone who I wanted to be. It encourages me to ask questions and to kill the assumptions. It might vary from person to person, but it reflects my thoughts and views.

Similarly, you can also talk about your experience and what had pulled you to UX, how you feel after entering, etc. Your definition of UX is your own, and it should be what you value the most.