I’m a math teacher for both junior high and elementary school in Japan.
I’m using this blog to providing information about education for Japanese people. But from now on, I want to try to spread my message to people all over the world. This is my first writing in English. It’s my challenge. I cannot use English well, so please forgive me if I write something rude.
I was curious about what mathematical terms that we learn in Japan are called in English. My research led me to an interesting discovery. Conversely, I thought that English speakers would also find something to discover in knowing Japanese mathematical terminology.
So, this page describes how to say mathematical terms in Japanese.
Plane figure
Circle
Circle is called “円（en）” in Japanese. For English speakers, “yen” may be easier to read. The “yen” is the Japanese currency unit. There is a theory that the Japanese currency unit is called “yen” because the coins are shaped circle.
It’s so simple!
Triangle
Triangle is called “三角形（sankakukei）” in Japanese.
”三（san）” means “three” in Japanese.
”角（kaku）” means “angle” in Japanese.
”形（kei）” means “shape” in Japanese.
So, “三（san）角（kaku）形（kei）” means “three-angles-shape”.
Besides,
- Isosceles triangle is called “二等辺三角形（Nitohen sankakukei）” in Japanese.
- Right triangle is called “直角三角形（Chokkaku sankakukei）” in Japanese.
- Equilateral triangle is called “正三角形（Sei-sankakukei）” in Japanese.
Tetragon
Tetragon is called “四角形（Shikakukei）” in Japanese.
”四（shi）” means “four” in Japanese.
”角（kaku）” means “angle” in Japanese.
”形（kei）” means “shape” in Japanese.
So, “四（shi）角（kaku）形（kei）” means “four-angles-shape”.
Besides,
- Square is called “正方形（Seihokei）” in Japanese.
- Rectangle is called “長方形（Chohokei）” in Japanese.
Parallelogram is called “平行四辺形（Heikoshihenkei）” in Japanese.
Diamond is called “ひし形（Hishigata）” in Japanese.
Another Plane figure
It is the same idea as the “triangle” and “Tetragon”. This idea is the same for everything else.
- Pentagon is called “五角形（Gokakukei）” in Japanese. ”五（Go）” means “five” in Japanese.
- Hexagon is called “六角形（Rokukakukei）” in Japanese. ”六（Roku）” means “six” in Japanese.
- Heptagon is called “七角形（Nanakakukei）” in Japanese. ”七（nana）” means “seven” in Japanese.
- Octagon is called “八角形（Hachikakukei）” in Japanese. ”八（hachi）” means “eight” in Japanese.
etc…
3D figure
Cube is called “立方体（Rippoutai）” in Japanese.
Rectangular prism is called “直方体（Chokuhoutai）” in Japanese.
triangular prism is called “三角柱（Sankakuchu）” in Japanese.
Pentagonal prism is called “五角柱（Gokakuchu）” in Japanese.
Hexagonal prism is called “六角柱（Rokukakuchu）” in Japanese.
Cone is called “円錐（Ensui）” in Japanese.
Triangular pyramid is called “三角錐（Sankakusui）” in Japanese.
Square pyramid is called “四角錐（Shikakusui）” in Japanese.
Finally
These knowledge may not be particularly useful just because you know them. However, even if they are just [trivia], there is no harm in knowing them. I am sure that many of them were unexpectedly unknown to you.
Thank you for reading to the end.
