See W3C documentation for the XHTML table model.
Sets the horizontal (line) alignment inside a table cell
The align attribute is used in two different ways. 1) It specifies the horizontal alignment for the entire cell (such as “center” or “justify”. 2) It is used for aligning values in table cells on a particular character within the cell, commonly a decimal point. Alignment on a particular character requires that three attributes be set in the XML document:
|Center align the cell contents
|Align the text on the character identified with the char attribute
|Fully justify cell contents (right and left justification)
|Left justify cell contents
|Right justify cell contents
|Restriction: This attribute may be specified if the element is used.