devalue  (v.) reduce the value of a currency against other currencies（货币）贬值

[例]  The war inside the country severely hurts the consumers’ confidence and devalues its currency in the international financial market.

[同义词]  depreciate, devaluate

devaluation  (n.) the deduction in the value of a currency against other currencies（货币）贬值

[同义词]  depreciation, deflation

differentiate  (v.) to make something different or highlight the difference between two things区别

[例] It is hard to differentiate the one from the other.

[同义词]  distinguish, set apart,separate

differentiation (n.) making sure that a product has distinguishing features区别

[例] Line 1 and Line 2 have little differentiation.

price differential (n) the difference in prices charged for the same product in different shops, or for different products in a range 差价

[例] The price for this air-conditioner is the lowest in Shanghai, and if you can find lower price for it within 15 days, we will refund the price differential to you.