Isosceles
/aɪˈsɒsəliːz/noun
A triangle with two sides of equal length.
Did you know?Ancient Greek geometers named the triangle by imagining its two matching sides as equal legs, turning anatomical language into mathematical symbolism.
Etymological Timeline
Ancient Greek
Greek
ἴσος (isos)
“Equal or even”
Ancient Greek
Greek
σκέλος (skelos)
“Leg”
Ancient Greek
Greek
ἰσοσκελής (isoskelēs)
“Having equal legs; specifically, having two equal sides”
Late Antiquity
Latin
isoscĕles
“A triangle with two equal sides”
13th Century
Middle English
isosceles
“A geometrical figure or triangle with two equal sides”
Modern English
English
isosceles
“Having two equal sides, especially of a triangle”