equilateral
Americanadjective
noun
-
a figure having all its sides equal.
-
a side equivalent, or equal, to others.
adjective
noun
-
a geometric figure having all its sides of equal length
-
a side that is equal in length to other sides
Other Word Forms
Derived Forms
Etymology
Origin of equilateral
From the Late Latin word aequilaterālis, dating back to 1560–70. See equi-, lateral
Explanation
A shape is equilateral if all the sides are the same length. In geometry class, people learn about many shapes, such as triangles and squares. A square is equilateral, because all of its sides are the same length. A rhombus is also equilateral — its sides are also the same length. A triangle can be equilateral too, but not a scalene triangle, which has three sides of different lengths. The word equal should help you remember what equilateral means. You can also use it as a noun for an equilateral shape.
Vocabulary lists containing equilateral
STAAR Grade 5 Mathematics: Geometry — Triangles, Polygons, and Prisms
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STAAR Grade 8 Mathematics: Geometry and Measurement, List 2
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Geometry, List 2
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
Lisa will use the same principle but fire its beams over a much greater distance, and between three identical spacecraft arranged as an equilateral triangle.
From BBC • Jan. 25, 2024
These related tilings are made of shapes called polyiamonds, simple tiles formed by combining equilateral triangles.
From Scientific American • Apr. 10, 2023
Often, the sandbox game is about the quiet joys of pastoral life, where players construct homesteads, rear livestock, and grow crops in a world made up entirely of perfectly equilateral cubes.
From Slate • Mar. 24, 2023
She added an equilateral oval line, slightly off-center within the disk’s perfect circle.
From Los Angeles Times • Jan. 6, 2023
There was an ancient school-bus-yellow sign with a black circle holding three equilateral yellow triangles.
From "The Smartest Kid in the Universe" by Chris Grabenstein
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
