What HTML tag is used to define an unordered list?

The tag used to define an unordered list in HTML is

. This tag is specifically designed to create a list where the items are marked with bullets instead of numbers, which is characteristic of unordered lists. When you use the
tag, you typically nest the individual list items within it using the
• tag, which designates each list item.

  In contrast,

  is used for ordered lists, where items are numbered, indicating a sequence. The tag is not a valid HTML element, and
  1. is used for listing individual items within either an unordered or ordered list, rather than defining the list itself. Therefore, when you want to create a list that does not follow a specific order, the correct choice is to utilize the
     tag.