The th table header tag is used to denote the first row(s) of a table: It (they) will be made up differently from the other rows in the table. Exactly how it is made up depends on the format. In printed documentation (latex) a line will be drawn under the row. In HTML, the font and background may be formatted differently.
The th tag can only occur inside a table tag, and can contain only td tags.
Example:
Will be formatted approximately as
Cell (1,1) | Cell (2,1) |
Cell (1,2) | Cell (2,2) |
See also: tr (184), table (177)
The topic tag starts a topic page or section. A topic page or section is not linked to an identifier in some unit: it exists by itself. It must be inside a package or module tag. It must have a name attribute (for cross-referencing). If it appears inside a package, it can be nested: a topic may be inside another topic tag.