Car batteries are normally rated in ampere-hour What does this mean?

Car batteries are normally rated in ampere-hour What does this mean?
simple.

lets imagine you have a 70 Amp Hour battery (technically an accumulator, not a battery, but thats not important).

the designation means it can sustain a 1 ampere continuous drain for 70 hours, or a 70 ampere drain for 1 hour. these figures are usually validated by certain temperature ranges etc,,

hope this helps.