Meantime (one word) means the time between two events, as in “in the meantime.” Mean time (two words) is a timekeeping or averaging term, as in Greenwich Mean Time or mean time between failures. In the meantime vs mean time debate, use one word if you could say “meanwhile.”
Meantime vs Mean Time Quiz: Test Yourself
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Meantime vs mean time trips up confident writers because the two spellings sound identical. The difference is simple: meantime is one word for the gap between two events, while mean time is two words for a timekeeping or averaging term. Below you’ll find clear definitions, examples and a few memory tricks.
| Term | Meaning | Part of speech / Category | Example sentence |
|---|---|---|---|
| meantime | The time between two events | Noun | In the meantime, I’ll start dinner. |
| meantime | During the time in between | Adverb | The results arrive Friday. Meantime, keep working. |
| mean time | Time based on the motion of an imaginary “mean sun” | Noun phrase (timekeeping) | Greenwich Mean Time is a well-known time standard. |
| mean time | The average time something takes or lasts | Noun phrase (engineering, IT) | The mean time to repair is 40 minutes. |
| Meantime | A London brewery and beer brand | Proper noun (brand) | Meantime Brewing Company began in Greenwich. |
What does meantime mean?
Meantime means the time between two events. Dictionaries list it as both a noun and an adverb, and it has been in English since the 14th century.
You will usually meet it in the phrase “in the meantime”:
- We’re leaving at six. In the meantime, let’s pack the car.
- The plumber arrives tomorrow. Meantime, use the downstairs bathroom.
Meantime is a close cousin of “meanwhile,” and the two are largely interchangeable. The main nuance is that meanwhile can also mean “at the same time,” while meantime leans toward “in the gap before something else happens.” Other substitutes include “in the interim” and “for the time being.”
What does mean time mean?
Mean time (two words) is time measured by an imaginary “mean sun” that moves at a perfectly steady rate. It is also called mean solar time, and its most famous use is Greenwich Mean Time (GMT).
Before standard time zones, each place kept its own local mean time, so clocks differed from east to west. The word “mean” here is the maths sense: average. Because a real solar day varies slightly, mean time smooths it into a steady average.
The same logic explains common engineering and IT metrics:
- Mean time between failures (MTBF): the average time a system runs before it fails.
- Mean time to repair (MTTR): the average time it takes to fix something.
In each case, “mean” means average and “time” is the thing being averaged, so the words stay separate.
Meantime vs mean time: which one should you use?
Use one word when you mean “in the interim,” and two words when you mean clocks or averages. Two quick checks settle almost every case:
- Swap in “meanwhile.” If the sentence still works, write meantime.
- Swap in “average time.” If the sentence still works, or you’re naming a time standard like GMT, write mean time.
If you aren’t sure, you probably need the one-word meantime, because it is by far the more common everyday need.
Is “in the mean time” ever correct?
As a way of saying “meanwhile,” no: the standard spelling is “in the meantime,” and readers and editors tend to mark the split version as an error. You may spot it in print, but that doesn’t make it standard.
The split spelling is only right when “mean time” is genuinely a separate phrase, for example: “The mean time to complete the task was 12 minutes.” There, you could swap in “average time.”
What is Meantime, the brand?
Meantime, with a capital M, is also the name of Meantime Brewing Company, a London brewery founded by Alastair Hook in Greenwich in 1999 and now owned by Asahi. Its Greenwich brewery closed in 2024, and the brand returned to Greenwich in late 2025 with a venue called The Dial.
The capital letter and a beer or business context are your clues. In an ordinary sentence, lowercase meantime is just the word.
What are the most common meantime vs mean time mistakes?
In the mean time, I’ll book the tickets.
In the meantime, I’ll book the tickets.
The clocks in London followed Greenwich Meantime.
The clocks in London followed Greenwich Mean Time.
Our meantime to repair is two hours.
Our mean time to repair is two hours.
For the mean time, use the side door.
For the meantime, use the side door.
The meantime between failures is 400 hours.
The mean time between failures is 400 hours.
How can you remember which one to use?
- The meanwhile trick: if “meanwhile” fits, glue the words together. Meantime and meanwhile both start with “mean” fused to the next word.
- The average trick: if you can say “average time,” keep the words apart, because “mean” is doing its maths job as a separate word.
- The GMT trick: Greenwich Mean Time always has three separate, capitalised words. Whenever you see GMT or MTBF, the middle word stands alone.
Frequently asked questions
Is it meantime or mean time?
Both exist, with different meanings. Meantime (one word) means the time between two events. Mean time (two words) is a timekeeping or averaging term, such as Greenwich Mean Time.
Is meantime a real word?
Yes. Dictionaries list meantime as both a noun and an adverb, and it has been used in English since the 14th century.
Is it ‘in the meantime’ or ‘in the mean time’?
The standard spelling is ‘in the meantime.’ The split version ‘in the mean time’ is usually treated as a mistake unless you really mean an average time.
What is the difference between meantime and meanwhile?
They are largely interchangeable. Meantime is more often used as a noun, as in ‘in the meantime,’ while meanwhile is usually an adverb and can also mean ‘at the same time.’
What does mean time mean in Greenwich Mean Time?
It refers to mean solar time, which is based on an imaginary sun moving at a steady rate. ‘Mean’ means average, so Greenwich Mean Time is the average solar time at Greenwich.
Conclusion
The meantime vs mean time question comes down to meaning: one word for the gap between events, two words for clocks and averages. Try the “meanwhile” swap and you’ll rarely get it wrong. Share this with someone who mixes these up.