Displacement:The change in position of an object. For example, if you start at point A and end up at point B, your displacement is the straight-line distance between those two points.
Acceleration:The rate at which an object's velocity changes over time. If you're driving in a car and step on the gas pedal to go faster, you're experiencing acceleration.
Constant Velocity: When an object's velocity remains unchanged over time. If you're driving in a straight line at a constant speed, your velocity remains constant.