The ballroom hold is the classic hold for a man and a lady dancing a couple dance like the Waltz.
Ideally, the man and woman face each other and advance so that they are in body contact and slightly offset. This is so that if the man moves his foot forwards, it will go between the Lady's feet and he will not tread on her toes. The same applied in reverse of course.
The man's right hand goes behind the lady's back and rests under her left shoulder blade and her left hand rests on the man's upper arm. They can either join the other hands or the lady can rest hers on the man's, but the arms should be extended but slightly bent and held at just below shoulder height.