Cold Cranking Amps refers to the amperes that the battery can supply in a cold condition. The term originated from vehicle batteries which had to deliver the needed power to crank (start) the engine.
When the vehicle is in a cold condition, the electrolyte in the battery becomes denser.In the engine, the lubricating oils also becomes more viscous.
Thus, the vehicle draws more power than it normally would when in a cold climate. The battery should be able to deliver the high current which will be drawn by the starter motor of the engine.
Vehicle Batteries usually contain the Cold Cranking Amps. The Cold Cranking Amps is also specified by the Starter Motor which will draw the current.
Therefore, it is important that the battery is chosen such that it is able to deliver the required Cold Cranking Amps. The CCA number is an important value in the battery.