Definition of SQUARE ML (㎖)

Question

This is a very simple thing, I suppose, I'm having hard time to find out, what is the meaning of Square ML (㎖) symbol? Square MiLe, Square MilliLiter, Square Maximum Likelihood, or totally something else?

I can find these symbols belonging to the physical symbol set in unicode set starting from:

0x3371  13169   SQUARE HPA  ㍱

and going to:

0x33DD  13277   SQUARE WB   ㏝

http://www.ssec.wisc.edu/~tomw/java/unicode.html

Along ML are:

0x3395  13205   SQUARE MU L ㎕
0x3396  13206   SQUARE ML   ㎖
0x3397  13207   SQUARE DL   ㎗
0x3398  13208   SQUARE KL   ㎘

And yes, this seems to be more of physics topic, not that much mathematics...

Answer 1

Disclaimer: This post will use a lot of unicode characters that may not display properly in some environments.

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The characters in the CJK Compatability block are mostly symbols for units used in Japanese, with some crossover into other languages like Chinese and Korean. Most of them have a name in unicode with "SQUARE" (as in SQUARE ML) because the character is made from multiple symbols designed to fit the square space that a character would fit in for proper Chinese/Japanese/Korean typesetting. For example, compare the spacing of "c""m" vs. "cm" in this string: 三ｃｍ三cm因.

㎖ means milliliter, and this meaning is shown on the Japanese and Korean wikipedia pages for "liter". You can also see is referenced in math courses. For example, a middle school math student is asking about the relationship between ㎤ (a single character for $\mathrm{cm}^3$) and ㎖ here.

There are many other units and related symbols in the CJK Compatability block, including ㏑ for $\ln$, ㏒ for $\log$, ㎯ ($\mathrm{rad}/\mathrm{s}^2$) for the SI measure of angular acceleration, ㌫ for "percent", and ㌦ for "dollar(s)", etc. The last two are written in Japanese phonetic characters.