diameter

diameter — 名詞

1. the distance across a round shape, measured by a line passing through its centre

1.名詞B1
釋義

直徑

通過圓心連接圓周的直線

the distance across a round shape, measured by a line passing through its centre and meeting the edge at two opposite points; also used for the numerical length of that line.

例句

Hari measured the diameter of the tree trunk before cutting it down.

Hari 在砍倒那棵樹之前，先量了量樹幹的直徑。

measure the diameter of [round object]

A pipe with a wider diameter allows more water to flow through it.

直徑較大的管子可以讓更多水流過。

wider diameter

同義詞
  • width

    general measurement from side to side; diameter specifically requires going through the centre of a round shape

  • breadth

    similar to width, but less precise; not restricted to round shapes

文法句型

the diameter of [something]

[number] in diameter

常見錯誤

❌The diameter of the circle is half the radius.
✅The diameter of the circle is twice the radius.
💡diameter = 2 × radius, not the other way around.
❌Draw a diameter line across the square.
✅Draw a diagonal line across the square.
💡diameter only applies to round shapes, not squares or rectangles.

2. a unit that tells you how many times larger an object appears when seen through

2.名詞C1
釋義

倍率

光學儀器的放大倍數

a unit that tells you how many times larger an object appears when seen through a lens, microscope, or telescope, compared to how it looks with the naked eye.

例句

Folake observed the cells under a microscope at four hundred diameters magnification.

Folake 在放大四百倍的顯微鏡下觀察細胞。

[number] diameters magnification

The telescope's two hundred diameter setting made the craters on the moon easy to see.

望遠鏡的兩百倍放大設定讓月球上的隕石坑清晰可見。

[number] diameter setting

同義詞
  • magnification

    more common and general term; 'diameters' is restricted to lens specifications

  • power

    informal shorthand ('the scope's power is 20×'); less precise than 'diameters'

文法句型

[number] diameters

at [number] diameters magnification

用法筆記

This sense is almost always used with a number (e.g., '40 diameters', '100× diameter'). In modern technical writing, '×' or 'times' is often preferred over 'diameters'.

常見錯誤

❌The microscope has a diameter of 400.
✅The microscope magnifies to 400 diameters.
💡the number refers to magnification power, not the physical size of the lens opening.