Since EVs are very quiet, it could be a rolls machine, which is basically a treadmill for a car. They are used for running tests on vehicles and are outrageously loud. They can be used during prototyping. In a car factory it's at the very end of the assembly line and sometimes used for debugging vehicles that have come off the line with issues.
Here is what I would call a chassis dyno http://www.maha.de/roller-function-tester-fps-2700.htm
These are very very noisy, because the tires are moving at 70 or 80 mph (whatever you set) and make as much noise as tires going 70 down a highway (only 1 axle though!)
A rolling road is different in that the floor moves under the car, not just rollers under 1 or 2 axles. Like this http://www.qmtmag.com/images/Windshear_RR_05.jpg
The chassis dynos are noisy, these are super noisy.
Disclosure: I sold Maha dynos from 96-2000 with SnapOn/Sun branding, about 40 of them.
I thought a dyno is a mechanism that a standalone engine can be rigged up to on the bench to test it under (typically computer-) controlled conditions, measure its output, simulate different driving conditions, etc.
I've never heard any term except dyno (or dynamometer), but I much prefer those terms simply because it's more apparent to someone that doesn't have an understanding of engine & car testing.
I'm a fan of names that give insight into what the thing/product/service/company actually does.
dynos can measure at the engine (in which case they measure brake horse power) or at the wheels. Most individuals are more familiar with the ones that measure at the wheels, as that's how they would measure the effect of after-market modifications.
