Certain calibers such as the 300 Winchester Magnum are often called flat shooting.
What does that mean and why would a hunter care that the caliber is flat shooting when selecting a rifle to go hunting with?
Bullets follow a parabolic arc as seen below,
As you can see the yellow line is a bullet fired from a longer barrel which results in a higher velocity and thus less drop over distance. In this case the yellow line is a flatter shooting rifle.
Cartridges that are regarded as flatter shooting have one or both of two things going for them, they are traveling at a much higher velocity to start with and or have a better ballistic coefficient resulting in less drag.
See for example 6.5 Creedmore vs. 308 Winchester.
The reason that this matters is that with a flatter shooting cartridge you don't have to get the range to the animal as accurately because the bullet is dropping less. This leads to the concept of point-blank-range as fully explained here