If something is subcooled, it has been cooled below its normal temperature.
Subcooled things are usually very cold and might be used in machines or in cooking.
Examples:
The subcooled water turned into ice.
She put the subcooled food in the fridge.
The subcooled air made everyone shiver.
The subcooled drink was so cold, it froze my tongue!
The subcooled metal was as cold as the North Pole.
He used subcooled liquid to make the ice cream.