Many people wonder whether they should write meantime or mean time. The answer depends on what you want to say. Meantime (one word) is the correct choice when you mean “during the intervening period” or “meanwhile.”
Mean time (two words) is usually a technical term used in engineering, statistics, and reliability analysis, such as Mean Time Between Failures (MTBF) or Mean Time To Repair (MTTR).
People often confuse these forms because they sound identical. This guide explains the difference, origin, pronunciation, spelling rules, examples, and professional usage so you can choose the correct form with confidence.
Quick Answer
The correct spelling depends on the context.
- Meantime is an adverb or noun meaning during the intervening period or meanwhile.
- Mean time is a technical noun phrase that refers to an average amount of time, especially in engineering and reliability studies.
| Expression | Correct Use | Example |
| Meantime | ✅ Everyday English | I’ll finish the report. In the meantime, you can review the data. |
| Mean Time | ✅ Technical English | The server has a high mean time between failures. |
Examples
- ✅ The package will arrive tomorrow. In the meantime, please check your email.
- ✅ Engineers measured the mean time to repair the equipment.
- ✅ We will announce the results next week. Meantime, continue your work.
- ✅ The company improved its Mean Time To Failure (MTTF).
The Origin of Meantime or Mean Time
The word meantime comes from combining the words mean and time into a single compound word. Over many years, frequent use caused the two words to merge into the closed compound meantime.
Originally, writers often used mean time as two separate words. As the English language evolved and spelling became standardized, meantime became the accepted form when referring to the period between two events.
However, mean time did not disappear completely. It developed a different meaning in technical fields.
Today, the two forms have different purposes:
- Meantime → Refers to the period between events.
- Mean time → Refers to an average measurement of time.
Why Do Both Spellings Exist?
English contains many words that changed from open compounds into closed compounds.
Examples include:
- Meantime
- Meanwhile
- Today
- Tomorrow
- Tonight
At the same time, technical fields continued using mean time because the word mean refers to the mathematical average.
That is why both spellings still exist today but with different meanings.
British English vs American English Spelling
Unlike words such as colour/color or organise/organize, there is no spelling difference between British English and American English for meantime.
Both varieties use:
- Meantime for everyday writing.
- Mean time for technical and scientific writing.
| Usage | British English | American English |
| Everyday meaning | Meantime | Meantime |
| Technical meaning | Mean Time | Mean Time |
| Academic writing | ✅ Same | ✅ Same |
| Business writing | ✅ Same | ✅ Same |
Examples
British English
- The train is delayed. In the meantime, please remain on the platform.
American English
- We’ll finish the project tomorrow. Meantime, complete the remaining tasks.
Engineering Example
- The device has an excellent Mean Time Between Failures (MTBF).
Both British and American dictionaries recognize these meanings without changing the spelling.
Pronunciation of Meantime or Mean Time
The pronunciation of meantime and mean time is almost identical, which is one reason many writers confuse them.
Correct Pronunciation
Meantime: /ˈmiːn.taɪm/
Mean time: /miːn taɪm/
Both sound like:
MEEN-time
The main difference is not pronunciation but meaning and usage.
| Word | Pronunciation | Meaning |
| Meantime | /ˈmiːn.taɪm/ | During the period before something happens |
| Mean time | /miːn taɪm/ | Average amount of time |
Spoken Examples
When someone says:
“I will call you tomorrow. In the meantime, relax.”
They mean:
“Until then” or “during this waiting period.”
When an engineer says:
“The mean time to repair is two hours.”
They mean:
“The average repair time is two hours.”
Because both expressions sound similar in conversation, understanding the context is more important than pronunciation.
Why People Confuse Meantime or Mean Time
Many English learners and writers confuse meantime and mean time because both forms contain the same words and have the same pronunciation.
Here are the main reasons behind this confusion.
1. Similar Spelling
The words mean and time appear together in both forms.
This makes people think they are interchangeable, but their meanings are different.
Compare:
- Meantime = a period between events
- Mean time = an average measurement of time
2. Confusion Between Compound Words
English has many words that change from two words into one word over time.
Examples:
| Closed Compound | Open Form |
| Meantime | Mean time |
| Today | To day |
| Tomorrow | To morrow |
| Tonight | To night |
Because English contains both open and closed compounds, learners often struggle to know which version is correct.
3. Different Contexts
The word meantime is common in everyday communication, while mean time is mostly used in technical fields.
Examples:
Everyday English:
- I will prepare dinner. In the meantime, watch a movie.
Technical English:
- The machine’s Mean Time Between Failures improved after maintenance.
4. Similar Sound Creates Mistakes
In spoken English, listeners cannot see the spelling.
Someone may hear:
“mean time”
and assume it should always be written as two words.
However, context determines the correct spelling.
5. Influence of Mathematical Meaning
The word mean has a special meaning in mathematics.
In statistics, mean means an average value.
Examples:
- Mean score
- Mean temperature
- Mean time
This technical meaning is different from meantime, which has nothing to do with averages.
Which Spelling Should You Use?
Choosing between meantime and mean time depends completely on your meaning.
Use “Meantime” When You Mean “Meanwhile”
Use meantime in everyday communication when talking about something happening between two events.
Examples:
- The doctor will arrive soon. In the meantime, please wait here.
- I am looking for a new job. Meantime, I am improving my skills.
- The website is being updated. In the meantime, users can access the old version.
Use “Mean Time” for Average Time
Use mean time when discussing measurement, data, or technical information.
Common examples:
- Mean Time Between Failures (MTBF)
- Mean Time To Repair (MTTR)
- Mean Time To Failure (MTTF)
These terms are common in:
- Reliability Engineering
- Computer Science
- Manufacturing
- Maintenance Planning
- Statistics
- Data Analysis
Audience-Based Advice
| Audience | Recommended Usage |
| Students | Use meantime for normal writing |
| Bloggers | Use meantime for general content |
| Business Writers | Use meantime unless discussing measurements |
| Engineers | Use mean time for technical data |
| Researchers | Use both depending on context |
| ESL Learners | Remember the meaning before spelling |
For most daily writing, emails, essays, and social media posts, meantime will be the correct choice.
Common Mistakes with Meantime or Mean Time
Many writers use meantime and mean time incorrectly because they focus on spelling instead of meaning. These mistakes are common in emails, academic writing, business documents, and online content.
| Incorrect Usage | Correct Usage | Explanation |
| ❌ I will call you. Mean time, check the details. | ✅ I will call you. Meantime, check the details. | Here, the meaning is “during this period,” so use meantime. |
| ❌ In the mean time, please wait. | ✅ In the meantime, please wait. | The phrase in the meantime is always written as two words for the complete phrase, but meantime itself is one word. |
| ❌ The machine’s meantime between failures is 500 hours. | ✅ The machine’s mean time between failures is 500 hours. | Technical measurements use mean time. |
| ❌ The average repair period is called meantime. | ✅ The average repair period is called mean time. | “Mean” refers to an average calculation. |
| ❌ I will finish this task in the mean time. | ✅ I will finish this task in the meantime. | Everyday waiting situations use meantime. |
Common Writing Problems
Using “Mean Time” for Everyday Situations
A common mistake is writing:
❌ I am busy now. Mean time, you can start the project.
The correct form is:
✅ I am busy now. Meantime, you can start the project.
Because the sentence refers to a temporary period, not an average measurement.
Using “Meantime” in Technical Reports
Another mistake happens in engineering or scientific documents.
Incorrect:
❌ The system has a good meantime between failures.
Correct:
✅ The system has a good mean time between failures.
Technical terms require mean time because they describe calculated averages.
Meantime or Mean Time in Everyday Examples
The correct choice depends on the context. Below are examples from different areas of communication.
Emails
Meantime:
- The manager is reviewing your request. In the meantime, please prepare the required documents.
- I will send the final version tomorrow. Meantime, you can check the draft.
Mean Time:
- The report shows the mean time required to complete customer support requests.
News Articles
Meantime:
- The investigation will continue. In the meantime, officials are collecting more information.
- The company is preparing for the launch. Meantime, customers can register online.
Mean Time:
- The research calculated the mean time between different events.
Social Media Posts
Meantime:
- Waiting for the results. In the meantime, enjoying the journey.
- The update is coming soon. Meantime, stay connected.
Mean Time:
- Our latest analysis shows the mean time users spend on the platform.
Academic Writing
Meantime:
- The researchers collected additional data. In the meantime, participants continued the study.
Mean Time:
- The study calculated the mean time required for each experiment.
Business Communication
Meantime:
- The contract is under review. In the meantime, both teams can continue discussions.
Mean Time:
- The maintenance department tracks the Mean Time To Repair (MTTR) of equipment.
Easy Trick to Remember Meantime or Mean Time
A simple memory trick can help you choose the correct spelling.
Memory Trick 1: “Meantime = Meanwhile”
If you can replace the word with meanwhile, use:
✅ Meantime
Example:
- I will finish the work. Meantime, you can prepare the presentation.
Replace it:
- I will finish the work. Meanwhile, you can prepare the presentation.
The meaning stays the same, so meantime is correct.
Memory Trick 2: “Mean = Average”
If the word mean refers to a calculation or average value, write:
✅ Mean Time
Examples:
- Mean temperature
- Mean score
- Mean time
- Mean value
Remember:
Mean = Average → Two separate words
Meantime = Meanwhile → One word
Quick Rule
| Meaning | Correct Form |
| During this period | Meantime |
| Average amount of time | Mean Time |
This simple rule works for emails, essays, professional writing, and technical documents.
Comparison Table
The following table shows the key differences between both forms.
| Feature | Meantime | Mean Time |
| Number of words | One word | Two words |
| Meaning | During the period before something happens | Average amount of time |
| Grammar Role | Adverb or noun | Noun phrase |
| Everyday English | ✅ Common | ❌ Rare |
| Technical Writing | ❌ Not usually used | ✅ Common |
| Business Emails | ✅ Common | Sometimes used |
| Engineering | ❌ Incorrect for measurements | ✅ Correct |
| Statistics | ❌ Incorrect | ✅ Correct |
| Example | In the meantime, wait here. | The mean time to repair is two hours. |
Quick Difference
Meantime = Meanwhile
Example:
The project will start next month. In the meantime, prepare the documents.
Meaning:
Until then.
Mean Time = Average Time
Example:
The mean time to complete the process is 30 minutes.
Meaning:
The average duration.
FAQs
Is meantime one word or two words?
Meantime is one word when it means “during the intervening period” or “meanwhile.” It is the standard form used in everyday English.
Is mean time ever correct?
Yes. Mean time is correct when referring to an average measurement of time, especially in technical fields such as engineering, statistics, and data analysis.
What is the difference between meantime and mean time?
Meantime refers to a waiting period between events, while mean time refers to an average amount of time.
Example:
- Meantime: In the meantime, I will prepare dinner.
- Mean time: The mean time required for repair is three hours.
Is “in the mean time” correct?
In modern English, the preferred phrase is:
✅ In the meantime
Although older writing may contain in the mean time, modern style guides recommend the one-word form meantime.
Are meantime and meanwhile the same?
Yes, in most situations meantime and meanwhile have similar meanings.
Example:
- I will finish the report. In the meantime, you can review the data.
- I will finish the report. Meanwhile, you can review the data.
Both sentences are correct.
Do British and American English spell meantime differently?
No. Both British English and American English use meantime in the same way. The spelling does not change between regions.
What does mean time mean in engineering?
In engineering, mean time refers to an average measurement of time.
Common examples include:
- Mean Time Between Failures (MTBF) – average operating time between system failures.
- Mean Time To Repair (MTTR) – average time needed to fix a problem.
- Mean Time To Failure (MTTF) – average lifespan before failure.
Conclusion
The choice between meantime and mean time depends on meaning, not spelling alone. Use meantime when you mean “meanwhile” or “during the waiting period.”
Use mean time when discussing an average measurement of time in technical areas like engineering, statistics, or reliability analysis. Both forms are correct, but they are used in different situations.
Remember the simple rule: meantime = meanwhile, mean time = average time. Following this rule will help you write clearer emails, academic work, professional documents, and everyday English with confidence.
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Hi, I am Mary Norris, and I write clear and insightful grammar blogs on Syntaxiffy.com.
On Syntaxiffy.com, I focus on English grammar, usage, and writing accuracy to help readers improve their language skills.
