English Reference

Word

diameter

Phoneticsdi·am·e·ter

US/daɪˈæmətɝ/

UK/daɪˈæmɪtɐ/

Definitions

01distance across a circle

B1 · Math

n. the length of a straight line that goes from one side of a circle to the other, passing through the center.

n. the length of a straight line segment passing through the center of a figure, especially a circle or sphere, and terminating at the periphery.

“The pipe has a diameter of ten centimeters, so it should fit perfectly.”

“To calculate the circumference accurately, the engineer first measured the inner diameter of the cylinder using a digital caliper.”

Pitfall

The diameter from the circle is ten centimeters.

The diameter of the circle is ten centimeters.

Use the preposition 'of' to link the measurement to the object being measured.

Synonyms

Antonyms

02the line itself

B2 · Math

n. a straight line that divides a circle into two equal halves by passing through the middle.

n. a chord that passes through the center of a circle or sphere.

“Draw a diameter across the circle to show where to cut the paper.”

“The geometry problem required students to construct a diameter that was perpendicular to the given chord.”

Synonyms

axiscenterline

03maximum distance in a space

C2 · Math

n. the largest possible distance between any two points in a specific area or shape.

n. the maximum distance between any two points in a metric space or the maximum eccentricity over all vertices in a graph.

“The diameter of this network is small, meaning any two points are closely connected.”

“In graph theory, the diameter of a graph is defined as the greatest distance between any pair of vertices.”

Technical

Usage

Used primarily in advanced mathematics, topology, and graph theory.

Synonyms

maximum width

Etymology

From Old French diametre (French diamètre), from Latin diametros, from Ancient Greek διάμετρος (diámetros) (γραμμή (grammḗ)) (diametros grammē, “line measuring across”), from διά (diá, “across”) + μέτρον (métron, “measure”). By surface analysis, dia- + -meter.

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

This entry

Level
B1 · Intermediate
Frequency
Common
Updated

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English Reference