differential

Concise Oxford English Dictionary © 2008 Oxford University Press:
differential /ˌdɪfəˈrɛnʃ(ə)l/ chiefly technical

▶adjective

• 1 constituting or depending on a difference; varying according to circumstances or relevant factors.

• 2 Mathematics relating to infinitesimal differences or to the derivatives of functions.

▶noun

• 1 a difference.

  ■ Brit. a difference in wages between industries or between categories of employees in the same industry.

  ■ Mathematics an infinitesimal difference between successive values of a variable.

• 2 a gear allowing a vehicle's driven wheels to revolve at different speeds in cornering.

– derivatives
differentially adverb.