'abbr' sets the abbreviated text for the cell and replace the cell contents
<HTML> <BODY> <table border="1"> <tr> <td abbr="C1"> Cell 1 content </td> </tr> <tr> <td abbr="C2"> Cell 2 content </td> <td abbr="C3"> Cell 3 content </td> </tr> </table> </BODY> </HTML>