1. ah, used to express surprise, agreement, joy, pain, dislike, or other emotions or reactions depending on what the person means by the statement: "Ah! So you didn't want to listen to me."

"Ah, yes, now I understand why you didn't come to the meeting."

2. ha, used as an exclamation of victory, confusion, surprise, discovery, or annoyance; or to express satisfaction that something bad has happened to a person who deserved it, or to indicate a feeling of victory.

A measure of the flow of current (in amperes) over one hour when the rate of flow is one ampere; equal to 3600 coulombs (standard international unit of electric charge).

Used to measure battery capacity.