namest

name of starting column for this entry. Name of leftmost column of span. The value must be some colname in a colspec of the current tgroup. A namest on an entry with no nameend specification indicates the single column so named, though colname is usually used for such a specification. If neither namest nor colname occur, the entry goes in the next column in sequence to the right, skipping over any encroachment from a prior row via entry morerows=N. It is an error if the namest value is not defined in a colspec for the current tgroup. 
Default: IMPLIED (implies this attribute has no 
          effect on spanning)