Position x(t):
Where a particle is at any given time.

Velocity v(t):
How fast and in which direction the particle is moving, ALSO the derivative of Position.

Acceleration a(t):
The rate of change of the change in position, ALSO the derivative of Velocity.

Speed:
The absolute value of velocity, AKA velocity without direction.

Speeding Up/Slowing Down:
When the signs of velocity and acceleration are the SAME the particle is speeding up
When the signs of velocity and acceleration are DIFFERENT the particle is slowing down

Displacement:
How far away from the starting point the particle has moved (uses integrals though)

Distance:
Simply the total distance traveled, so it is always positive or 0.