Disparity contains the Latin dis, meaning "apart" or "non-", so a disparity is a kind of "nonequality". The word is often used to describe a social or economic condition that's considered unfairly unequal: a racial disparity in hiring, a health disparity between the rich and the poor, an income disparity between men and women, and so on. Its adjective, disparate (accented on the first syllable), is often used to emphasize strong differences.