<OL> </OL>

The OL tag marks up an ordered list of items. Each item in the list must be marked up with an LI, and each one will have a number in front of it when displayed on the browser screen. The appearance of the number can be changed with the TYPE attribute:

1 - Arabic numbers (default) (1, 2, 3, 4, ...)
a - Alphanumeric, lowercase (a, b, c, d, ...)
A - Alphanumeric, uppercase (A, B, C, D, ...)
i - Roman numbers, lowercase (i, ii, iii, iv, ...)
I - Roman numbers, uppercase (I, II, III, IV, ...)

START tells where the list starts. COMPACT tells that the list contains only short items, so it can be rendered in a more compacted way.

For more info on lists see the Lists Tutorial.