The UA is free to put the caption above, below, or at the side of the table. The TR element contains zero or more TD or TH elements, viz. See below under TH and TD for an explanation of the exact layout of cells within rows. The UA normally renders the two slightly differently, for example TH elements can be centered and in bold face, TD elements are left aligned in a normal face. Cells can contain text as well as block-like elements, such as paragraphs, lists and other tables.
Cells can span multiple rows and columns, thereby pushing other cells aside.
See the rules for positioning cells below. The value must be a positive integer. The number specifies how many columns this cell occupies. The value must be a positive integer. It tells the UA how many rows the cell occupies.