THANKS

May someone tell me the meaning of THANKS please?
For those who finish reading this? Mind to drop some comments and tell me the meaning or definition of THANKS?
Sometimes, THANKS are useful in our daily life. It means a lot.
This are some definition that I found from net...

THANKS mean:
1. To express gratitude, appreciation, or acknowledgment to: She thanked them for their hospitality.
2. Usually, thanks. a grateful feeling or acknowledgment of a benefit, favor, or the like.
3. Have oneself to thank, to be personally to blame; have the responsibility.
4. Thanks to, because of; owing to...
5. Thank you, (used interjectionally to express gratitude, appreciation, or acknowledgment, as for a gift, favor, service, or courtesy).


This is what I found from the net... Are there all correct? THANKS just only use from the positive site? I don't know... That's why I need all of U to help me...
TELL ME WHY......