equilateral
adjective
Did you know?
Since equi- means "equal", the meaning of equilateral is easy to guess from its roots. The word is mostly used in geometry. The standard polygons (many-sided geometrical shapes)—the pentagon, hexagon, octagon, etc.—are assumed to be equilateral if we don't say otherwise; an equilateral rectangle has the special name square. But triangles are particularly important, and many triangles are not equal-sided. The standard polyhedrons (many-sided solids) are also equilateral. Most common is the cube, all of whose sides are square. The tetrahedron has four triangular sides and thus is a pyramid with a triangular base, unlike the pyramids of Egypt with their square bases.
Examples of equilateral in a Sentence
Katrina Cossey, Parents, 12 July 2023
This substantial set comes with 100 pieces, including squares (large and small) and triangles (equilateral, right and isosceles).
—Jessica Hartshorn, Good Housekeeping, 19 Dec. 2022
Waldo has floppy ears shaped like perfect equilateral triangles and feet too big for his lanky body, which continues to grow.
—Gemma Tarlach, Discover Magazine, 25 Nov. 2014
The set includes 48 regular squares, eight large squares, eight thick-sided squares, eight squares that look like windowpanes, 16 small and 16 large equilateral triangles plus 16 isosceles triangles.
—Jessica Hartshorn, Good Housekeeping, 19 Dec. 2022
See all Example Sentences for equilateral 
Dictionary Entries Near equilateral
Cite this Entry
“Equilateral.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/equilateral. Accessed 23 Nov. 2024.
Copy CitationKids Definition
equilateral
adjective
Share