synchromesh
Pronunciation: /ˈsɪŋkrə(ʊ)mɛʃ/
noun
- a system of gear changing, especially in motor vehicles, in which the driving and driven gearwheels are made to revolve at the same speed during engagement by means of a set of friction clutches, thereby easing the change: these gearboxes only had synchromesh on higher gears
Origin:
1920s: contraction of synchronized mesh