gears
n. countable B1 Intermediate US //ˈɡɪɹz// UK //ɡˈiəz// gears
n. the metal wheels with teeth that lock together to make a machine move. You use them to change the speed or power of a car or bicycle.
n. a set of toothed wheels that mesh together to transmit motion and power within a mechanical system. Often refers to the specific ratio settings in a vehicle's transmission.
The bike has twenty-one gears for climbing steep hills.
You should shift into lower gears when driving down a steep mountain road to control your speed.
The clock's internal mechanism consists of several interlocking brass gears that must be perfectly aligned to maintain accurate time over many years.
Usage
Often used in the plural when referring to a vehicle's transmission system or a complex machine.