Happiness ~ noun
1. the quality or state of being happy.
2. good fortune; pleasure; contentment; joy.
Joy ~ noun
1. the emotion of great delight or happiness caused by something exceptionally good or satisfying; keen pleasure; elation
2. a source or cause of keen pleasure or delight; something or someone greatly valued or appreciated:
3. the expression or display of glad feeling; festive gaiety.
4. a state of happiness or felicity.
Joy ~ verb (used without object)
5. to feel joy; be glad; rejoice.
Joy ~ verb (used with object)
6. Obsolete. to gladden.
Definitions from Dictionary.com
What stands out to you the most after looking at the definitions? For me, it is that "happiness" is a "state of being happy" versus the "a source or cause of keen pleasure or delight" that we find in joy. Joy isn't just a state of being, it is a source for us. Can you imagine if everyone went through their day looking to this source of Joy. My joy is found through my relationship with God and my Christian faith.
My daughter and students make me happy yet the joy I have as a source to my being allows me to be happy even when life isn't too "happy", you know what I mean? It's not easy but oh my gosh, it is so worth it...