Description Specifies a column, a vertical portion of a <entry>. The default values come from the <tgroup>, <thead> or <tfoot> starting the current group. Each <colspec> is for a single column, so it properly has a column number, column, implicitly in order starting from 1, and an optional colname by which it is known when used in any <spanspec> or in <entry>. A <colspec> set on <thead or <tfoot> should be complete for all columns. It overrides those on the containing <tgroup> and applies to just the <thead> or <tfoot>. If there is no <colspec> used within <thead> or <tfoot>, then the <colspec> of the containing <tgroup> is used. <colspec>s from the containing <tgroup> apply to <tbody>.