Here will be an explanation of what inheritance is, but until then I'll defer to the T:A wiki.
Arms of Telos is unique in that it lets you tune the inheritance values for each weapon to your liking. Think of it like being able to tune a car to your racing style. Right now, you can modify these values in your client config. In addition to being able to set the inheritance percentage, you can also select between multiple types of inheritance.
Full: Projectiles will inherit your velocity vector in all directions.
Forward: Projectiles will only inherit your velocity in your forward direction. Projectiles will end up hitting what you were pointing at, but their travel speed will be augmented by your speed in your forward vector.