Might be better for a math or datacomm exchange, but I'll try here first:

Given that "rate" means the number of times that an event occurs in a unit of time, what is the opposite/inverse of that term? Ie, what is a term for the time between events?

"Latency" comes to mind but is not quite right since it generally refers to the time between cause and effect, not between essentially identical events.

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    As always happens, about 2 minutes after I ask the question it comes to me: Period. (No, not the punctuation mark.)
    – Hot Licks
    Commented Apr 9, 2014 at 15:51
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    Welcome to EL&U. What is wrong with time (e.g. elapsed time or processing time or whatever kind of time you are marking)?
    – choster
    Commented Apr 9, 2014 at 15:52
  • @choster - "Time" is a bit ambiguous -- not clear whether it's a duration or a specific point on a timeline.
    – Hot Licks
    Commented Apr 9, 2014 at 15:56
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    And I guess "interval" also works.
    – Hot Licks
    Commented Apr 9, 2014 at 16:06
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    As 'rate' may be a variable, 'period' may not always be applicable. Commented Apr 9, 2014 at 18:23

5 Answers 5


If something is happening repeatedly, we say the value for rate (or frequency) increases if it starts happening more often in a given time-span. Conversely, if it starts happening less often we say the interval is increasing.

interval - a space between things, points, limits, etc.


In economics, the term in [sparse] use seems to be inverse rate. Otherwise, it looks like the English language doesn't have an appropriate word.

In electrical engineering, a similar concept is conveyed by resistance (the inverse of conductance), which is a measure of how much effort is required to achieve a flow of current. EE's have developed a set of mental tools to manipulate and work with these concepts.

The word interval works for quantifying discrete events (e.g., minutes per customer), but it just feels weird when quantifying continuous values (e.g., hours per kilometer).

It seems prudent to define a word in the language to convey the concept. It's just silly that so many questions on the GRE and GMAT revolve around manipulating inverse rates, as if it's hard to do. It's only hard to think about when we don't have a simple word to describe it.

  • Yeah, let's put a congressional committee on that.
    – Hot Licks
    Commented Feb 20, 2015 at 17:35

In physics the rate at which a repeating event occurs is the frequency. The time between events is the period.


Consider "interstice:"

interstice: 2 : a short space of time between events.

  • I gotta consider my audience -- computer nerds. They'd be looking for a roadmap.
    – Hot Licks
    Commented Apr 9, 2014 at 17:10
  • @HotLicks Well, then consider "downtime" and 'timeout." :-)
    – Elian
    Commented Apr 9, 2014 at 17:16

takt time

Takt time is the average time between the start of production of one unit and the start of production of the next unit, when these production starts are set to match the rate of customer demand.


  • If you quote someone else's words, it's essential that you make this clear (eg using quotation marks or blockquote formatting) and acknowledge the source. It's not only polite to give the original author credit, it also avoids the more serious charge of plagiarism. I've edited your post accordingly, but please include correct attribution in future :-) Commented Dec 12, 2018 at 2:54

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