equilateral

[ ee-kwuh-lat-er-uhl, ek-wuh- ]

adjective

1. having all the sides equal:

   an equilateral triangle.

noun

1. a figure having all its sides equal.
2. a side equivalent, or equal, to others.

equilateral

/ ˌiːkwɪˈlætərəl /

adjective

1. having all sides of equal length

   an equilateral triangle

noun

1. a geometric figure having all its sides of equal length
2. a side that is equal in length to other sides

equilateral

/ ē′kwə-lăt′ər-əl /

1. Having all sides of equal length, as a triangle that is neither scalene nor isosceles.

Derived Forms

• ˌequiˈlaterally, adverb

Other Words From

• equi·later·al·ly adverb
• none·qui·later·al adjective
• none·qui·later·al·ly adverb
• sube·qui·later·al adjective
• une·qui·later·al adjective
• une·qui·later·al·ly adverb

Word History and Origins

Origin of equilateral¹

From the Late Latin word aequilaterālis, dating back to 1560–70. See equi-, lateral

Example Sentences

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

On the other hand, if one has three coins available, there are suddenly two different arrangements that seem space-saving: one either lines them up side by side or places them along the corners of an equilateral triangle.

From Scientific American

These related tilings are made of shapes called polyiamonds, simple tiles formed by combining equilateral triangles.

From Scientific American

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

Euclid’s first task—Book 1, Proposition 1—was to show that given any line, he could make an equilateral triangle, i.e., a triangle with three equal sides, with that line as one side.

From Literature

Related Words

• rectangular