means The state of being unequal — a gap in size, amount, rights, or opportunity between people or things.

from From Latin inaequalitas, built from in- ('not') plus aequalis ('equal'), which comes from aequus, 'level, even, fair' — the same root that gives us 'equator' and 'equity.' English borrowed it through Old French in the late Middle Ages, first describing uneven surfaces and unmatched quantities before it came to weigh the unevenness between human lives.