What does scalene mean?
Scalene is the standard term for a triangle with three sides of different lengths. It is important in geometry because it distinguishes one kind of triangle from equilateral triangles, whose three sides are equal, and isosceles triangles, which have at least two equal sides. The adjective can also be applied to the scalene muscles, a group of three muscles in the neck that help move the neck and help with breathing. In ordinary writing, “scalene” is most often encountered in descriptions of triangles, such as “a scalene triangle,” while “scalene muscle” is the usual anatomical expression. Its usefulness lies in providing a precise label for a shape or structure that cannot be described by the broader term “unequal-sided.”
Having three sides of different lengths; describing a triangle with no equal sides.
"The proof shows that the triangle cannot be scalene."
Most commonly used in geometry.
Relating to or denoting one of the scalene muscles of the neck.
"The therapist examined the scalene muscles for tenderness."
Used in anatomical and medical contexts.
A scalene triangle has no matching sides, making it the geometric opposite of the perfectly symmetrical equilateral triangle.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of scalene
The word comes through Latin from Greek skalēnos, meaning “unequal” or “uneven.” The Greek term was applied to triangles with no equal sides and also contributed to anatomical terminology for the scalene muscles. Latin scalenus gave rise to English forms such as “scalenus,” “scalenoid,” and “scalenectomy.”
How scalene is actually used
In general use, “scalene” is primarily a geometric term. In anatomy, it refers to the scalene muscles of the neck.
Easily confused with scalene
A scalene triangle has three unequal sides, whereas an isosceles triangle has at least two equal sides.
A scalene triangle has no equal sides, while an equilateral triangle has three equal sides.