syn·chro·mesh 
(sĭngkrə-mĕsh′, sĭn-)
(sĭngkrə-mĕsh′, sĭn-)n.
1. An automotive gear-shifting system in which the gears are synchronized at the same speeds before engaging to effect a smooth shift.
2. A gear in such a system.
- on one's radar screen
- on one's radar screen
- on (one's) soapbox
- on one's soapbox
- on (one's)/the way
- on (one's) /the way
- on one's the way
- on (one's) toes
- on one's toes
- on (one's) uppers
- on one's uppers
- on one's way
- on one/the onehand
- on order
- on own
- on own account
- on own ground
- on own hook
- on own initiative
- on pain of
- on paper
- on pins and needles
- on principle
- on purpose
- on radar screen