Q:

What is the difference between Jhana and Samadhi?

In Sutta pitaka we find two Suttas namely Jhana sutta and Samadhi sutta.
 What is the difference?
http://www.accesstoinsight.org/tipitaka/an/an04/an04.041.than.html
http://www.accesstoinsight.org/tipitaka/an/an09/an09.036.than.html

A:

Samadhi is a general term for concentration. Jhanas are stages you achieve in Samatha meditation when your concentration reaches a certain level. 
To give an analogy, Samadhi is like the temperature of ice. When the temperature reaches a certain level, it becomes water. That's like reaching the first Jhana. If you keep heating, it will become steam. That is like reaching the second Jhana and so on.

