I need to describe a process and I'm currently missing the right word. How do you call the time (the duration, not the moment of action) when e.g. a light-switch is set to "passing" i.e. the light is on? I thought about on time so even non-native speakers don't struggle with its meaning, on the other hand it sounds clumsy.

Is there a word for this?

  • It might help if you told us what the process is. Except for start time, I can't think of any generic term.
    – Mick
    Oct 18 '16 at 8:02
  • @Mick I'm talking about the time an actuator is switched on to do his job. This terminology is used to define the time how long it shall stay on this certain state. Oct 18 '16 at 8:15
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    Operating time? merriam-webster.com/dictionary/operating
    – user66974
    Oct 18 '16 at 8:50
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    So you're talking about the length of time that the switch was on for, the duration, not the clock-time at the instant when it was actually switched?
    – Andrew Leach
    Oct 18 '16 at 9:30
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    The relevant term would probably depend upon whether the switch turns itself off or is turned off manually. If it turns itself on and off by itself, you might call it the "on cycle" and "off cycle". But you wouldn't use terms like that if it was manually switched on and off.
    – ohwilleke
    Oct 18 '16 at 11:46

For a simpler term I would suggest running.

The second defintion from Merriam-Webster (linked above):

the activity of managing or operating something

To use in a sentence: "The light was running for 2 two hours".

In general the word run has a multitiude of definitions that bascially boil down to action over time.

Another come phrase although not a single word, would be run time. As in, "The current run time for the light is two hours".


For a switch you could say active. Other synonyms are engaged, operating and functioning.

For a machine (typically a computer) use uptime.

  • Thanks for the contribution, active, engaged, aso. are no words that could be assigned with a time in my opinion. And uptime is too heavyweight since it is not a system just an actuator, considering a situation with the lightswitch is really appropriate. Oct 18 '16 at 9:11

...during illumination time ....


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