D defs.my
Entry 4 senses · 2 variants Webster, 1913

Overdrive

/ōv'-ẽrd-rīvˌ/ · O·ver·drive · IPA /ˌəʊvə(ɹ)ˈdɹaɪv/
01 v. t. & i. To drive too hard, or far, or beyond strength.
  1. 1.
    To drive too hard, or far, or beyond strength.
02 n. A gearing device which causes the drive shaft of an automobile or other machine to rotate at a speed greater than that of the engine crankshaft.
  1. 1.
    A gearing device which causes the drive shaft of an automobile or other machine to rotate at a speed greater than that of the engine crankshaft.(Machinery)
  2. 2.
    The gear setting of a motor vehicle at which the overdrive{1} is operative; as, cruising at 80 mph in overdrive.(Automotive)
  3. 3.
    A state of unusually intense activity; as, when they got their new supercomputer, their research kicked into overdrive; one look at her made his heart jump into overdrive; -- used mostly of the activities of persons or groups.[fig.]