used to show a sudden feeling, such as one of surprise, pleasure, or understanding: Ah, so that’s what the problem was! (Definition of ah from the Cambridge Academic Content Dictionary © Cambridge University Press)

An ampere-hour or amp-hour (symbol: A⋅h or A h; often simplified as Ah) is a unit of electric charge, having dimensions of electric current multiplied by time, equal to the charge transferred by a steady current of one ampere flowing for one hour, or 3,600 coulombs.