Impressions represent the number of people your video has been shown to. This could be in a list of recommended videos on YouTube, or in viewers News Feed on Facebook.
Views on the other hand are a measure of the number of times your video has been watched. Read our Knowledge Base post to learn what counts as a view.
Your impressions will always be greater than your views, as not everyone will click to watch your video. Think it impressions and views as funnels. Your impressions is the top funnel, and some of those people will click to watch your video, of those that watch your video, some of them will go on to click on your profile or your call to action.