Generally someone who's age is in their late thirties. Also useful when you are approaching the age of 40, and you don't really want to admit you are right up against the big 4-0, you instead say "thirty late" because it could mean you are 37, instead of 39½.
That girl I went to school with is thirty late, she should know better than to be fooling around with a douchebag loser like that Rick guy.
by ChimneySweepGreg December 30, 2011