The dome is called an ushnisha (sanksrit; sometimes spelled usnisa or usnisha). It is usually described as a fleshy mound covered in hair. This extension of the Buddha's head symbolizes his enlightenment and wisdom.
Buddha.
buddha who started buddhism.
It is a pearl to symbolise wisdom.
after a leader died they has a head which reminded them of the dead leader
Akanishta
According to the Tipitika, he had a knob on the top of his head, that is, that was the shape of his head when he was born. This was said to be one of the 32 signs of a great man, destined to be either a world king or a Buddha.
It symbolises Buddha's wisdom.
I don't know the anawer
A domed hall is a rotunda.
It is called the Domed Rotunda
Actually from what i have heard is that it is actually disrespectful to rub his belly...he was a teacher of knowledge and enlightenment not of food. (The Buddha who gets his belly rubbed is the Laughing Buddha, aka Hotei. No relation to the one who started Buddhism.)
It symbolise count olafs tatow