Adds 8 (15 counting variations) new turrets for dealing with alien menace, as well as other military-related items. Good compliment to mods that add new biter types, like Rampant or Natural Evolution.
AoE is short for "Area of Effect" - AoE weapons hit everything within set radius of a target. In Factorio, examples of AoE weapons are Explosive Rockets, Explosive Cannon Shells, Poison/slowdown Capsules, Artillery Shells and, of course, Nukes.
The one example from Modular Turrets I suspect you're referring to are Gamma Beam Turrets. These fire a straight beam, hitting all enemies in a line (linear AoE).
