So, what you have there, if it's mil based, is a mil grid reticle. All the little lines and dots and crosses are milliradians and sub-tensions of milliradians and are referred to as a hashes or hashmarks. Some people call them ticks or tickmarks. The actual crosshair in one of these reticles would be the main center aimpoint where you zero, whether that’s a dot, a crosshair, or a circle, or what have you. An MOA based version would be an MOA Grid reticle.
Numerous companies have their own version but in the end, they are all essentially the same and perform the same function, just mils or MOA. I prefer mils. It's actually easier because everything is broken down to .1 of a mil. This means (if you're military and do everything in meters) your ranging measurements are simpler and more accurate, and your holds and measurements are simpler and more accurate. I highly encourage shooters to dump MOA and move to mil based reticles. The only question I would have is "is the reticle really a mil reticle?" Some of the cheaper scopes have reticles that are not accurate mil measurements.
A mil grid is not to be confused with a ballistic reticle/Christmas tree reticle. They are not the same. Those are calibrated for specific cartridges or families of like cartridges. Their precision usually disappears after about 400m. Ballistic Christmas tree examples would be a Pride Fowler Rapid Reticle, any ACOG or Elcan reticle, Nikon ballistics dots, etc.
The mil grid allows you to not only range a target, but lets you have a ballistic hold, allows for winds holds, measure known objects, and provides adequate leads on moving targets. The best thing they do for hunters, is allow a ballistic holdover and a wind hold capability for shots longer than 200-300m/yds. You can easily find your holds and wind holds for your gun and specific ammo with a ballistic calculator like a kestrel and print it into a little range card and tape it to your buttstock.
