Word Study
Isosceles
CIDE DICTIONARY
Isosceles, a. [L., fr. Gr. ; 'i`sos equal + leg.].
Having two legs or sides that are equal; -- said of a triangle. [1913 Webster]
OXFORD DICTIONARY
Isosceles, adj. (of a triangle) having two sides equal.
Etymology
LL f. Gk isoskeles (as ISO-, skelos leg)
For further exploring for "Isosceles" in Webster Dictionary Online