L is for List <li>
The list element <li> is used with either the ordered list <ol> or
unordered list <ul> to make (guess what?) a list.
But this list can also do service (and often does) as a navigation
Alternatively you could use a one column table for a navbar.
Those that know about web design sem to be very down on tables. But
why is a list-created navbar preferable to a table--created one?