Does speed always mean fast

Sometimes "speed" can be slang for an illegal narcotic that acts as a stimulant, specifically Methamphetamine. Another way to think of it is for speed its more general since its not specifically describing the motion. For example think of a general Word like temperature its not saying specifically hot or cold. As for fast it would be a more specific Word and using the same example it could be considered to be something like hot is to cold as fast is to slow. So to recap speed is a form of measure like temperature its just not giving it a description. I hope this helps you i'm not to good with Words.