這兩個名詞都有「差異」的意思，但它們差異的程度卻有很大的不同。discrepancy 意為「差異，不同，不一致；不一致或不相符之處」(difference, lack of similarity or agreement, inconsistency)，可當可數或不可數名詞用，後面通常接介系詞 between 或 in，如 There is some discrepancy between their two descriptions. (他們兩人的描述有些出入)；There was a discrepancy in the two reports of the accident. (關於那起事故的兩份報導有矛盾之處)；There were some discrepancies in the statement he gave to the police. (他給警方的陳述有些地方不一致)。顯然地，discrepancy 所指的差異在程度上似乎不大。
Disparity 意為「差異，不同，不等，不一致；懸殊」，通常是指重大的差異，不相等，顯著的不同或根本不同 (important difference, inequality, something incongruous, markedly distinct, or fundamentally different)，同樣可當可數或不可數名詞用，而後面亦通常接介系詞 between 或 in，如 The disparity between their proposals made compromise unlikely. (他們的提案差很大，使得尋求折衷變得不可能)；There is still a disparity in salaries among people doing the same job. (同工不同酬的情況仍然存在)；There is (a) considerable disparity in the rates of pay for men and women. (男女薪資的比率相差懸殊)。必須注意的是，disparity 前面若有修飾語，則該修飾語必須是能夠凸顯「差很大」、「懸殊」的字眼，如 considerable, great, significant 或 wide 等形容詞。