Elevation Per Turn is when you turn a rifle scope turret for 360 degrees to the same spot where you started. For example, when you see in specifications – elevation per turn is 10 MRAD or 100 cm / 100 m, this means when you make 1 turn with turret, the point of impact on the target will be moved for 100cm on 100m range.
If elevation per turn is 24 MOA, this means that 1 turn the point of impact will be moved for 24 x 2.9 cm / 100 meters.
This information is mostly important for sport and tactical rifle scope where you often change the elevation. It’s much easier to use when the values for a turn are rounded (for example 20 MOA), but on tactical rifle scopes this mostly isn’t possible, because of big elevations, so the turrets had to be Multi-Turn (MT), what would even more complicate the use.
Source: Revija Lovec