Differential Amplifiers are operational amplifiers configured to amplify differential input signals but to supress or reject common-mode signals; they incorporate on-chip resistors to define the differential gain.

Instrumentation Amplifiers, Texas Instruments

Instrumentation amplifiers are composite differential amplifier blocks generally incorporating a classic three operational amplifier configuration. They provide high input impedance, very high common-mode rejection and allow differential gain to be accurately set via internal or external resistors. Differential amplifiers offer low DC offset and drift coupled with high open loop gain and low noise and are frequently used in high-precision test and measurement applications and electrically noisy environments.