adjective

of, showing, or depending on a difference; varying according to circumstances or relevant factors.

the differential achievements of boys and girls

distinctive,different,dissimilar,contrasting,divergent,disparate,contrastive,distinguishing,discriminating,discriminatory

noun

a difference between amounts of things.

the differential between petrol and diesel prices

difference,gap,gulf,divergence,disparity,discrepancy,imbalance,inequality,contrast,distinction