1.the quality of being thankful; readiness to show appreciation for and to return kindness
noun grat·i·tude \ˈgra-tə-ˌtüd, -ˌtyüd\
: a feeling of appreciation or thanks
The Free Dictionary says
grat·i·tude (grăt′ĭ-to͞od′, -tyo͞od′) n.
The state of being grateful; thankfulness
And finally from reference.com
1. the quality or feeling of being grateful or thankful:
So, what is gratitude?