Final answer:
An equilateral triangle is the term for a triangle where all sides are of equal length.
Step-by-step explanation:
The term that represents a triangle with all sides of an equal length is equilateral. An equilateral triangle is a polygon with three sides (tri- meaning three) where each side has the same length and each of the internal angles is 60 degrees.
In contrast, a scalene triangle has no sides of equal length, an isosceles triangle has at least two sides of equal length, and the term quadrilateral refers to a four-sided polygon, which is not a triangle at all.