Web Design in a Nutshell, 3rd Edition

Internal Table Elements

CSS 2.1 makes a distinction between table elements and internal table elements. A table element is any part of a table (including table and caption). Internal elements are just those elements that generate a cell (such as td or th), a row (tr), a row group (rowgroup), a column (col), or a column group (colgroup).

Internal table elements may have content, padding, and borders. Internal elements may not have margins and any margin settings provided will be ignored.