olemus
mitme klahvi korraga vajutamine
= pressing multiple keys at once

(a) juhusliku sisestusveana
= as a random input error
https://link.springer.com/chapter/10.1007/978-3-642-03655-2_16

(b) klaviatuuri erivõimalusena sisestuse kiirendamiseks
= as a special keyboard option to speed up input
https://en.wikipedia.org/wiki/Key_rollover

vt ka
https://en.wikipedia.org/wiki/Modifier_key