rhizoverbBeta
DictionarydiameterDistance across the center
noun

diameter

dye-AM-ih-tur/daɪˈæmɪtər/

The straight-line distance across a circle or round object through its center.

The red thread marks the disc's diameter through its center.

A flat circular wooden disc seen nearly overhead with one taut red thread from left rim through the marked center point to opposite rim; exactly straight across center, no radius-only line, no text.
Etymology
diaGreekacross, through
+meterGreeka measure

A diameter is a measure across a circle: the line passes through its center from one side to the other. The name also denotes the length of that line.

In context

The Olympic Vault0:32
diameter of about 22 cm. Women throw a lighter discus weighing 1 kg and measuring about 18 cm in diameter.
What Are The Rules Of Discus Throwing? - The Olympic Vault

More examples

  • A circle’s diameter is twice its radius.
  • Measure the pipe’s inside diameter before buying a connector.
  • These round pans have different diameters.

Forms

diameter · diameters

Similar words

width
Width measures across something without necessarily passing through its center.
span
Span measures the distance between endpoints, not necessarily through a center.