Reaction Force
The force that is equal in strength and opposite in direction to the action force, which acts simultaneously on whatever is exerting the action force
Newton's Third Law
Whenever one body exerts a force on a second, the second body exerts and equal and opposite force on the first
Force
Any influence that tends to accelerate an object; a push or a pull
Mass
The amount of matter in an object: a measure of an object's inertia
Acceleration
The rate at which velocity changes
Action force
One of the pair of forces described in Newton's 3rd law