what the unit?

A unit is usually -- but doesn't have to be -- 1 percent of your bankroll.
A unit is whatever you want it to be; but it is often recommended you make every wager for the same unit size so you don't get swept away when the losses come.

Basically, it's the amount that you would typically wager.

For example, I've got a unit of $100, so I would say something like this in a post:

Texas Tech @ SMU (+8) - Bet 1.10 units to win 1.00 units

In other words, I'm wagering $110 to win $100.

thanks for the input,great site and forum.