catflap.org Online Dictionary Query

  function application
       
          A function applied to (some of) its arguments.  If it is
          not applied to all its argument then it is a "{partial
          application".  Application is usually written in the form
          f(x) but some languages such as command-line interpreters and
          many functional languages use juxtaposition: f x.  Lisp
          places the parentheses around the whole application: (f x).