As a Noun: 1. In a vehicle, a part that allows one wheel to rotate faster than the other wheel when turning corners, for example. English - differential. Note: 1. There appears to be no commonly used Auslan sign for DIFFERENTIAL for most signers (but some signers represent this visually using these depicting signs, once they have established the topic). This suggested sign is a visual representation of the turning action of a round component rotating faster around another one. Source of this recommended sign: Victorian College for the Deaf.