PAL is an encoding that is used in some video games to restrict its use to a specific region. Use this tag if your question specifically relates to the PAL region locking of a game or console.
PAL is an encoding used to display picture on a television, using the standard of 50 fields, at 25 frames per second. It has been criticised as inferior to NTSC (60 fields, at 30 frames per second), but is used predominantly, across the world.
Encoding has been an issue with video games, in the past, as consoles would often be locked to only play games within their region. In the modern day, it is far more common for a console to be 'region free'.
This tag should be used in regards to PAL region encoding and region locking.
If your question is about PAL, itself, consider if your question is within context of the Arqade. PAL is used for encoding video games, but it is not a video game technology, as it is also predominantly used in other media. If your question undoubtabley is on topic, use this tag.
If your question is in context of a game being PAL encoded, potentially in regards to being region locked or its specific functionality, use this tag.
If your game is PAL encoded, but your question does not apply to region locking or the actual context of being PAL encoded, do not use this tag.
If you could replicate the same environment on a game encoded in NTSC, do not use this tag.