DN> Designated Number> if you've noticed in some of the members' picks, they play the same 2 numbers on every line. For example, Dennis plays the 25-26 in his lines for Super 7 draw. Some of the members call them their base numbers also.
the lotto glossary has some terms and abreviations like that in it. It's a short glossary & worth reading. you may get a hint at a new strategy even. I did. the link is the button on the bottom of the page.