Question about engines

I have a habit of always running a post game analysis with CMX to see where i blundered and so on, so always in the analysis window there is this thing saying DEPTH = 2/7 (the numbers always change).
So what does it mean? i have been trying to figure this one out for a while now and every reasonable explanation i have come up with have failed at some point 🙂

thanks in advance!

The first number represents the depth in ply(half moves) the engine has searched so a 14 would mean it looked 7 moves ahead in all lines, and the second number is selective depth,the computer analyzes forcing lines deeper (checks and captures) so a 18 means the longest line it has analyzed is 9 moves deep, the engine has to calculate the forcing lines to the end.

Many thanks! 😉