title: Any difference between First Class Function and High Order Function
body: <p>I'm wondering whether/what difference between <a href="http://en.wikipedia.org/wiki/First-class_function" rel="noreferrer">First Class Function</a> and <a href="http://en.wikipedia.org/wiki/Higher-order_function" rel="noreferrer">High Order Function</a>.</p>
  
  <p>I read through those two wiki pages and they looks rather similar.
    If they talking about same, why need two terminologies?</p>
  
  <p>Tried to google but have not found any useful thing.</p>