1. Distance vs. Displacement
Distance = A scalar equal to the length of the path taken to get between two points.
Displacement = A vector that points from an objects initial position to its final position and has a magnitude equal to the shortest distance between the two positions.

2. Speed vs. Velocity
Average Speed = A scalar equal ratio of the distance an object covers divided by the elapsed time.
Average Velocity = A vector quantity equal to the ratio of the displacement an object undergoes divided by the elapsed time.

3. Acceleration
Acceleration = A vector that points in the direction of the change in velocity and has a magnitude equal to the ratio of change in average velocity divided by the elapsed time.