A date
11^11
Today
A date
Easter
piyusha
It is: TODAY
Today
Today (considering you'll read this answer today).
A date or Today
If you write April 26, 2011, this contains only 5 letters, but unfortunately also contains numbers...
Even if you used roman numerals, it would still require more than 5 letters.
The word is TODAY. It does not use roman numerals.