PAL (Phase Alternation Line) Is the main European TV signal output.
The difference between PAL and NTSC (the American type in full: National Television Standards Committee) is that the NTSC syatem isn't as good in coloring as the PAL system but has a higher nuber of half-frame per second (PAL has 50, NTSC 60) wich makes tv images look more fluid.
These days tv's (especially in Europe) support both signals including a mix of both wich has the refresh from NTSC and coloring of PAL.
This system is also used as a country lock, meaning that sertain DVD's or tapes will only play if the system supports the signal.
"My TV support NTSC and PAL signal, it lets me watch normal tv in PAL and use my American game systems in NTSC"