A "Smart Key" is a modern keyless entry system used in vehicles and some buildings. It allows users to unlock and start their vehicle without physically inserting a key. Instead, the smart key communicates wirelessly with the vehicle, typically through a key fob or a smartphone app, enhancing convenience and security. Smart keys often come with additional features, such as remote start, trunk release, and even vehicle tracking. They use advanced technology like RFID (Radio Frequency Identification) or Bluetooth to ensure that only authorized users can access the vehicle, making them a popular choice in today's automotive market.