Linked from
The 17 pages that link to Speed, each with the reason it gives.
KnotNarrower topic: A knot is one particular unit for measuring this rate.
Metre per secondNarrower topic: Metres per second can express speed without specifying direction.
SpeedometerNarrower topic: A speedometer displays an estimate of this physical quantity.
Kilometres per hourNarrower topic: Kilometres per hour is one way to express this rate.
Miles per hourNarrower topic: Miles per hour is one specific unit for expressing speed.