# More common way to say “squared”, 二次方X or X的平方？

In English it's much more common to say "squared" than "to the second power", but the reverse seems to be true in Chinese. For example, m/s^2 is more commonly 米每二次方秒 (according to Google searches) than 米每秒的平方. Does this match sound right to 中国数学家?

• As the unit for acceleration, m/s^2 is often read as "米每秒每秒". As it means the change of speech (whose unit is 米每秒) per second (每秒). This would not apply to other units with ^n. – fefe Mar 13 '19 at 4:10

When using in maths, we say:
x 的平方 (or, x 的二次方, alternatively): The square of x
x 的立方 (or, x 的三次方, alternatively): The cube of x
xn 次方: The n-th power of x
x 的平方根 (or, x 的二次方根, alternatively): The square root of x
x 的立方根 (or, x 的三次方根, alternatively): The cube root of x
xn 次方根: The n-th root of x

When using in units in daily life, we say:
using 平方米 (or 平米) frequently rather than 二次方米 for square meters.
using 二次方秒 frequently rather than 平方秒 for square seconds.

I thinks it is because of that 平 means flat literally in Chinese, 平方 means flat square literally, maybe the word 平方 was created to describe the area size at first (actually it is the same like that the word square in English). When referring to the square of time units, people prefer 二次方 instead of 平方.

I think you don't bother to find what's correct, both 米每二次方秒 and 米每平方秒 are understandable.

Basically, there are some statute describe the general rule for unit pronounciation . But I can't find the data source, so I don't post the rule here.

My rule is, just like in english, read all x³ to 立方x, all xᒾ to 平方x expect /sᒾ .

kg/m³
kg        /     m³

kilograms per cubic-meter


In most cases $x \in {m,cm,mm,s}$, if oneday I have to read the gravitational constant G(6.67E-11 N*mᒾ/kgᒾ), I most probably read 每平方千克.

Below are reasons why "米每二次方秒" more common than "米每平方秒"(from the perspective of Bayesian inference.) I think it's just a convention. It's a huge project to find exactly why. For the pronunciations of other common units, you can also find them in my links.

## Statute law

It shows there are only one correct pronunciation.

1. 中华人民共和国国务院公报 page 572 中华人民共和国计量单位名称与符号方案 from 中国政府
2. 中华人民共和国计量单位名称与符号方案（试行） from 北京法院法规检索
3. 《中华人民共和国法定计量单位使用方法》 , it is hosted on serveral unofficial web, I cannot find an official site.

## Publication

This solved your question of "中国数学家" .

1. 大学物理(高等院校物理系列教材)
2. 常用非法定计量单位与法定计量单位的对照及换算表 from 中国大百科全书数据库 & 附录二 非法定计量单位与法定计量单位换算表 from CNKI jiangxi

## Web data

This solve "the most common" problem.

Use double quotation marks and search by yourself to see what use them! One publication only has one form

1. google books ( 194 compared to 9 )
2. google scholar ( 14 compared to 2 )
3. google result (15700 compared to 4960)

Don't use baidu, the result include "米每二次方秒" and "米每平方秒" even if you use double quotation marks.

## Argument against

baike

see the link above, it's self-contradictory.
Due to web incompatibility, I can't amend it.
Also, the *former* baike article don't have source material.


Metre per second squared -> 米每秒平方
米每二次方秒->Meter every second second
米每平方秒->Meter per square second


Baidu translate

Metre per second squared->米/秒平方
米每二次方秒 -> Metre every second square second
米每平方秒 -> Metres per square second


## Others

FWIW, believe Wikipedia, when can't find in Wiki then use baike.

As for mathematical formula x², it can be pronounced as either

X的二次方 (x to the power of two)

or

X的平方 (x squared)

As for mathematical formula x³, it can be pronounced as either

X的三次方 (x to the power of three)

or

X的立方 (x cubed)

As for mathematical formula x⁴, it can only be pronounced as:

X的四次方 (x to the power of four)

As for the unit of area “square metre” (m²), it is often pronounced as:

However, as for the unit of acceleration “metre per second squared” (m/s²), it is usually pronounced as:

It is mainly because 平方秒 (square second, s²) per se does not make much sense. Nothing is measured in square seconds.

In contrast, as for the unit of the current density “ampere per square metre” (A/m²), it is usually pronounced as:

Because 平方米 (square metre, m²) per se makes sense. Area can be measured in square metres.

• Well, How do you pronounce the gravitational constant G? /kgᒾ don't make sense. – Voyager Mar 12 '19 at 15:41
• @rambler 6.67408×10⁻¹¹ 牛顿平方米每二次方千克 – Victor Mar 13 '19 at 1:15

二次方X is not used commonly, though people may still understand what you are indicating.

For numbers:

You can say X(的)二次方 (not common)

or X(的)平方

or X(的)立方 (3rd power)

or X的n次方 (nth power, n > 3)

where (的) can be skipped.

For units:

You can say 平方X (2nd power)

or 立方X (3rd power)

or n次方X (nth power, n>3)

so for your example: m/s^2, most common way to say is 米每平方秒.

• most common way to say is absolutely 米每二次方秒 1.wiki zh.wikipedia.org/wiki/… 2.online search result in baidu 3. my experience – Voyager Feb 22 '19 at 18:21
• @rambler I wouldn't say absolutely in any terms about Chinese unless I know everywhere in China is using exactly same term. Worth mentioning that wiki isn't widely used in China (especially in main land). Also I am not sure what term you put into baidu translate, but Baidu encyclopedia did use 米每平方秒 as their entity title. And through my 14 years of standard education in China mainland I've never speak the term in way of 米每二次方秒. – tweray Feb 22 '19 at 19:34
• Perhaps it's the false memory phenomenon. Absolutely means in my memory, it's absolutely. I can't recall anyone ever having said 米每平方秒 before. Now I will revoke my downvote anyway. And the Baidu Encyclopedia isn't authoritative at all, just now, when I publish my article of "米每二次方秒", the button is useless because the website isn't compatible with chrome. You also know baike is not objective under the control of CCP. The editor is also not good enough, in my wiki experience. Even now the the baike page has symbol error in your paste link and the link in the edit guide of baike is also broken. – Voyager Feb 22 '19 at 20:17
• @rambler srsly I don't think there's any meaning for CCP to control how people speak meter per square second. And just a reminder wikipedia is never authoritative, it's also maintained by community, and wiki community is much less popular than baidu community in China. If you feel necessary I believe you can try find the best reference from Chinese math text book. I personally won't bother doing that. Since OP is only asking for most common way to speak in China, I just provided the most common way from my experience and education in China. – tweray Feb 22 '19 at 20:21

m/s^2 -> n/s (n = √m)

I am not sure if they will do that, I have never seen something like x/y^2, maybe.

• Any example for m/s^2 -> n/s (n = √m)? It 's incomprehensible. – Voyager Feb 25 '19 at 11:41
• @rambler Sorry, if it is fault , my idea XD – sunfy Feb 25 '19 at 11:51