Marine Cranking Amps - The amount of amps a battery can produce at 32°F.

CCA:

Cold Cranking Amps - The number of amps a battery can deliver for 30 seconds at 0°F and maintain 7.2 volts.

RC:

The amount of minutes a battery can be discharged to 10.5 volts by 25-amp discharge at 80°F.

Amp Hour (Ah or ah):

A unit of measure for a battery’s storage capacity obtained by the amount of amps a battery can be discharged (typically 1.75vpc) multiplied by the amount of hours @ 80F (26.7C) . Most auto/marine and light truck batteries are tested at a 20-hour discharge rate. Example: A 12-volt 100ah rated marine battery means that 5 amps can be discharged for 20 hours at 80°F (26.7C) before falling below 10.5 volts (6 cells X 1.75v)