You have a low coolant warning light. If this light comes on, your system is low on coolant and the engine may overheat.
The warning light should come on briefly, as a check, when you turn on the ignition.
When it comes on, you will also hear a warning tone for 10 seconds. See Engine Coolant and have your vehicle serviced as soon as you can.
This light may also come on if your vehicle is equipped with the automatic engine shutdown system and engine shutdown has begun.