Noun
An item carried on a key ring either as decoration or for security.
A passive wireless electronic device that usually uses RFID technology to control access to buildings, containers, computers, etc. by being placed near a detector.
An active wireless electronic device that controls access to buildings or vehicles, such as a remote control for a car door lock.
Hyponyms: electronic car key, plipper
key-fob
As long as the Smart Key fob is in your pocket or purse, you can open Sienna’s doors with the touch of a handle, and start or stop the engine with the push of a button. Source: Internet
As you get within three feet of your Prime, with the Smart Key fob in your pocket or purse, the interior lights will automatically illuminate, the driver's door can be unlocked with just a touch, and the vehicle can be started with a push of a button. Source: Internet