Distinguish between speed and velocity.

The short answer is that velocity is the speed with a direction, while speed does not have a direction.

Speed is a scalar quantity -- it is the magnitude of the velocity. Speed is measured in units of distance divided by time, e.g. miles per hour, feet per second, meters per second, etc.

Velocity is a vector quantity -- when giving the velocity we must specify the magnitude (the speed) and the direction of travel.