What does "headless" mean?

Question

While reading the QTKit Application Programming Guide I came across the term 'headless environments' - what does this mean? Here is the passage:

...including applications with a GUI and tools intended to run in a “headless” environment. For example, you can use the framework to write command-line tools that manipulate QuickTime movie files.

Answer 1

"Headless" in this context simply means without a graphical display. (i.e.: Console based.)

Many servers are "headless" and are administered over SSH for example.

Answer 2

You most likely know what a browser is. Now take away the GUI, and you have what’s called a headless browser. Headless browsers can do all of the same things that normal browsers do, but faster. They’re great for automating and testing web pages programmatically.