A windlass is a simple machine for lifting or pulling heavy things: a rope or chain is wound around a horizontal drum, and you turn the drum with a handle or a motor so the rope winds on and the load comes up. The classic picture is an old well — the bucket on a rope, and the handle you turn to bring it back up. On boats it is the machine at the front that hauls the anchor up, and that is the most common use of the word today, so if a sailor says windlass they almost certainly mean the anchor machine. It is a technical, rather old-fashioned word outside sailing. In ordinary life people say 'winch', and the two overlap a lot: many speakers treat them as the same thing. If you want the careful difference, a windlass has its drum lying sideways, across the pull, while a winch usually has the drum turning with the pull; but plenty of native speakers do not keep this apart. There is also a verb, 'to windlass' something up, but it is rare and you can go a lifetime without needing it.

絞盤、（船上的）起錨機、（井上的）轆轤