A polygon is a flat shape with three or more straight sides. A triangle is a polygon. A square is a polygon. The red stop sign in the street is a polygon with eight sides.

A polygon多邊形is a flat shape with three or more straight sides是一個有三條以上直邊的平面形狀。A triangle三角形is a polygon就是一種多邊形。A square正方形is a polygon也是一種多邊形。The red stop sign in the street街上的紅色停止標誌is a polygon with eight sides是一個八邊形。

The name is built from 'many' + 'angle' (corner), so it is really a 'many-corners' shape. Though actually, 'many' here does not mean 'a lot'. In school maths it only means more than two, so three is already enough.

The name這個名字is built from 'many' + 'angle' (corner)是由「many（多）」加上「angle（角）」組成的so it is really a 'many-corners' shape所以其實就是「多角」的形狀。Though actually不過其實'many' here does not mean 'a lot'這裡的many並不是指「很多」。In school maths在學校數學裡it只only means more than two只表示大於2so three is already enough所以3就已經夠了。

A circle is not a polygon, because a circle is a curve and has no straight sides to count.

A circle圓形is not a polygon不是多邊形because a circle is a curve因為圓是一條曲線and has no straight sides to count沒有直邊可以數。

People also stretch the word a little: on a map, a polygon can be any area drawn with straight lines; in computer pictures, a polygon is a tiny flat piece the machine uses to build a solid-looking thing. In careful maths some polygons are tidy (every side and corner the same) and some are messy, even with sides that cross.

People人們also stretch the word a little也會把這個字用得寬鬆一點: on a map在地圖上a polygon can be any area drawn with straight lines多邊形可以指任何用直線畫出來的區域; in computer pictures在電腦繪圖裡a polygon is a tiny flat piece the machine uses to build a solid-looking thing則是機器用來組成立體外觀物件的一小片平面。In careful maths在嚴謹的數學裡some polygons are tidy有些多邊形很工整(every side and corner the same)（每一邊、每一角都一樣）and some are messy有些則很不規則even with sides that cross甚至邊會互相交叉。

For a learner, keep the simple picture: flat, straight sides, three corners or more.

For a learner對學習者來說keep the simple picture記住這個簡單的畫面就好: flat, straight sides, three corners or more平面、直邊、三個角以上。