olemus
seadme järjestikune alamosa,

Wiktionary:
2. one of the portions of a device (such as a rocket or thermonuclear weapon) which are used or activated in a particular order, one after another
The first stage of the launcher burned out and separated after successfully boosting the payload onto a suborbital trajectory, but the engine of the upper stage failed to ignite to place the satellite into orbit.
10. (electronics) the number of an electronic circuit’s block, such as a filter, an amplifier, etc.
a 3-stage cascade of a 2nd-order bandpass Butterworth filter

amplifier stage -- võimendusaste
input stage -- sisendaste
multistage -- mitmeastmeline
output stage -- väljundaste

näiteid
https://en.wikipedia.org/wiki/Multistage_amplifier

https://en.wikipedia.org/wiki/Multistage_rocket