If you ski off-piste, you leave the usual marked slopes — the ones with signs, machines that flatten the snow, and other people sharing the same track. Those prepared tracks are called pistes. Off-piste snow can be deeper and quieter, and it can also be more dangerous, because there may be rocks, trees, or snow that can slide. The word belongs in ski towns and ski magazines. Though actually, “the usual slopes” already includes easy and hard marked runs; off-piste means you are not on those marked ones at all. People sometimes stretch it to mean “away from the usual path” in work or ideas, but the first picture is still snow.