Ordered, unordered and description lists, and why list markup beats a pile of divs.
HTML provides three kinds of lists: unordered (ul) for items where order doesn't matter, ordered (ol) for sequences where it does, and description lists (dl with dt and dd) for term-and-definition or key-value pairs. Only li elements should be direct children of ul and ol, and lists can be nested by placing a new list inside an li. The ol element also supports attributes like start, reversed and type to control numbering.
Lists matter beyond bullets: screen readers announce how many items a list has and let users jump between them, which is why navigation menus are conventionally built as a ul of links. A frequent mistake is using list tags purely for indentation, or building a 'list' out of divs and losing that built-in semantics. Remember that bullet appearance is a CSS concern (list-style), so removing bullets doesn't mean you should stop using a list.
What you'll walk away knowing