To be happy, the expression of pleasure, contentment, good-luck or good fortune.
Examples:
1. "The birth of the new baby brought great happiness to the family."
2. "The student was extremely happy with his good report."

Happiness is a positive emotion. Most of us see laughter as a sign of happiness, and can lead to good health. When you laugh there are many physiological responses that are happening through out your body. For instance:

• Increases blood pressure
• Increases heart rate
• Changes breathing
• Reduces levels of certain neurochemicals
• Provides a boost to the immune system

Also, the facial expressions that can accompany happiness are:

• raised corners, and drawn back lips (possible parting of the lips to show teeth)
• wrinkles from their nose to the corners of their lips
• wrinkles spreading outwards from corners of eyes