# Is there a word for"every four months?"

**URL:** <https://boards.straightdope.com/t/is-there-a-word-for-every-four-months/532824>\
**Category:** Factual Questions\
**Created:** [March 18, 2010, 12:41am UTC](https://boards.straightdope.com/t/is-there-a-word-for-every-four-months/532824 "2010-03-18T00:41:31Z")\
**Posts on this page:** 3\
**Page:** 2

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**Author:** ![Peter\_Morris](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/peter_morris/32/359_2.png) [@Peter\_Morris](https://boards.straightdope.com/u/Peter_Morris)\
**Post date:** [March 19, 2010, 3:28am UTC](https://boards.straightdope.com/t/is-there-a-word-for-every-four-months/532824/21 "2010-03-19T03:28:32Z")

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> [@Bytegeist](#):
>
> The “deci” prefix means “one tenth”. I think you meant “hepta **deka** weekly”.

I did consider that, but a number system based on 16’s is called hexadecimal, so I went for i instead of a.

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**Author:** ![Indistinguishable](https://avatars.discourse-cdn.com/v4/letter/i/90ced4/32.png) [@Indistinguishable](https://boards.straightdope.com/u/Indistinguishable)\
**Post date:** [March 19, 2010, 5:22am UTC](https://boards.straightdope.com/t/is-there-a-word-for-every-four-months/532824/22 "2010-03-19T05:22:42Z")

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And, even more familiarly, a number system based on 10 is called “decimal”. 🙂 But the “deci-” in there does still etymologically derive from a word meaning “a tenth”.

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**Author:** ![BigT](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bigt/32/12044_2.png) [@BigT](https://boards.straightdope.com/u/BigT)\
**Post date:** [March 19, 2010, 10:04am UTC](https://boards.straightdope.com/t/is-there-a-word-for-every-four-months/532824/23 "2010-03-19T10:04:03Z")

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> [@gotpasswords](#):
>
> [Trimestral](http://www.thefreedictionary.com/Trimestral)

Tri means three, and mestral means months. A trimester is a three month period. (Think about the common division in pregnancy.) While it is used in scholarly circles to refer to a three part system, this is because summer break is itself considered a trimester. It’s the opposite of how a semester works, which literallyrefers to a period of six months, but tends to only refer to a period of four months.

And, no, that doesn’t make it a good term to use, as it still tends to refer to half a year. It’s just that a “school year” is shorter than a real year.

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