Drive may also refer to gain for an amplifier or effects unit, and pushing an amp’s preamp to distort can cause overdrive. Overdrive is generally considered to be another word for distortion or clipping. When you overdrive something with too much level, it distorts. For guitarists, however, there is a distinction between overdrive and distortion. In the domain of guitar sounds distortion generally means extreme distortion and is associated with a buzzing or “fuzz” type of sound. To guitarists overdrive represents the guitar equivalent of the general or mechanical definition above. It is a state of (for lack of a better term) semi-distortion. A heightened concentration of harmonic energy and presence, but not the same as all-out distortion.
Drive is also a shortened term referring to hard drives and CD readers/writers in computers.