Sorry, couldn't help but chuckle about this.
See post above - HSS=High Speed Steel. The German transliteration would be something like HGS (Hochgeschwindigkeitsstahl), but in practice it's called Schnellarbeitsstahl
Sorry for being late.
More than 100 years ago we have had to use relatively soft steel for our tools.
Then the HSS arrived which for sure meant High Speed Steel in comparism to the before being common steel.
The german meaning of HSS was and is Schnellarbeitsstahl which has been said for High Speed ability as in your countries.
But.
Today these terms practically have nothing to do with speed - if you want speed, you have to chose HM Hard Metal or ceramic tools.
Today the only reason for HSS usage is the lower price (it's good enough for cutting aluminium and buttersmooth steel), and a good grinding behaviour which allows for grinding your own tools, let's say tools with special shapes.
You can grind it fast with simple Corund grinding tools.
For other usage I gave up using HSS long time ago.
The other thing is the hardness of steels.
HSS, often sold cheap as HSSR in craftman's supermarket is the weakest material which neither stands for long times nor is it able to cut or drill harder steel or stainless steel.
If you want to drill stainless steel you will switch to HSSE whereas "E" stands for an alloy with 8% Cobalt.
If you want more HM Hard Metal is the answer.
Try to mill wood with a handhold mill and HSS milling cutter; you will learn within minutes about steel not being able to drive fast and to stay long.