How do you define happiness?

Is there a way of defining happiness?
How do we know what happiness is? What I define as happiness might not be the same as you think of it.
For many people happiness lies in having a good amount of money and fame.
For others money is not that important. Many say that family comes first and money is a lower priority.

Well I have learned that Family does come first. I'd rather be poor and happy than rich and miserable.
With out my family and their love I will not be happy. I will survive but everyone need love.

How do you define happiness? What is happiness?