Which HTML tag is used to define an unordered list?

The tag used to define an unordered list in HTML is the <ul> tag. This tag is specifically designed to create a list of items that do not have a specific order, which is indicated by bullet points in most browsers. Each item within the unordered list is wrapped in a <li> tag, which stands for "list item."

This structure allows for clear and organized presentation of related items where the sequence does not matter. For example, when creating a shopping list or a list of features, the unordered list provides an effective way to group these items visually.

In contrast, the <ol> tag is used for ordered lists, which display items in a specific sequence, typically numbered. The <list> tag is not a valid HTML tag, and using it would not result in any expected behavior. The <li> tag serves a different purpose, as it denotes individual items within either an ordered or unordered list, rather than defining the entire list itself. Thus, the <ul> tag is fundamental for creating unordered lists due to its unique function within HTML.