thead — A table header consisting of one or more rows
thead (db.cals.thead) ::=
Header rows are always rendered at the beginning of the table.
This element is expected to obey the semantics of the CALS Table Model Document Type Definition, as specified by OASIS Technical Memorandum TM 9502:1995. Header rows are often presented in an alternate typographic style, such as boldface.
In paged media, if a table spans across multiple pages, header rows are printed at the top of each new page.