People mean it differently. I think there are 3 main ways of counting it.
A) Last quarter of the year.
B) Last 2 months (10 weeks)
C) December
C is the most usual way to do it.
BTW, to your 2nd line, I too believe the Ps3 will beat the Ps3 in holiday sales.
http://www.vgchartz.com/games/userreviewdisp.php?id=261
That is VGChartz LONGEST review. And it's NOT Cute Kitten DS