the.com/judaism

means The monotheistic religion and way of life of the Jewish people, built on the Torah, the covenant with God, and centuries of law, tradition, and interpretation.

from Traces back through Latin 'Iudaismus' and Greek 'Ioudaismos' to Hebrew roots tied to 'Yehudah' (Judah), one of the twelve tribes and later the southern kingdom from which the word 'Jew' itself descends. The '-ism' is a later Greek-style suffix slapped on to name the whole system of belief and practice — so the word literally means something like 'the way of the people of Judah,' turned into an '-ism' by outsiders describing it from the edges before Jews widely used the term themselves.