A Page View represents each time a user visits a page. This means that a single user loading the same page 5 times in a single session will generate 5 pageviews.
Unique Page Views represent a total of pageviews generated by a user during the same session. This means that if the same user loads a page 5 times in a given session, it's only calculated as 1 unique pageview. This is why pageviews will always outnumber unique pageviews