Added 9 October 2026 gearbox /ˈɡɪəˌbɒks/ noun Categories: ThingsRare Words noun ! Definition from WordNet 3.1, Princeton University. Pronunciation from Wiktionary, via Kaikki.org. More about gearbox at Wordnik → Where our words come from → The shell (metal casing) in which a train of gears is sealed. Origin From gear + box. From Wiktionary, via Kaikki.org (CC BY-SA) Related Words: synchromeshtransaxlegearshiftdriversteeringmechanismtoolboxboxgearmachinerycarton Back to today's word