Here are some words that use "gear" as a noun:
* Top gear: The highest gear in a transmission.
* Low gear: The lowest gear in a transmission.
* First gear: The first gear in a transmission.
* Second gear: The second gear in a transmission.
* Reverse gear: The gear used for reversing.
* Drive gear: The gear that transmits power to another gear.
* Steering gear: The mechanism that controls the direction of a vehicle.
If you are thinking of a specific type of word, please provide more context and I can help you further.