row

Identifies the row information in a thead or tbody element. Default values come from the enclosing thead, tbody, or tgroup attribute values for like-named attributes.
The number of columns consumed by the entrys in a row including their spans, and by columns encroached by an entry with morerows from a prior row of a tgroup, shall not exceed the cols attribute value in effect for this tgroup. It is left up to the implementation how to handle the situation when more than one entry would fill any column of a row, including by spanning or straddling. It is recommended that an authoring or editing implementation or any implementation that verifies the compliance of the table markup to this Memorandum offer the option of producing a warning message when it encounters such markup. It is an error for an authoring or editing implementation to produce a table with such conflicting markup.
If the number of columns consumed is less than the number of columns specified in the tgroup's cols attribute, then the missing entrys (without spanning or straddling) are implicitly present, and their colsep and rowsep rulings are inherited.