fe·lic·i·ty 
(fĭ-lĭsĭ-tē)
(fĭ-lĭsĭ-tē)n. pl. fe·lic·i·ties
1.
a. Great happiness; bliss.
b. An instance of great happiness.
2. A cause or source of happiness.
3.
a. An appropriate and pleasing manner or style: felicity of expression.
b. An instance of appropriate and pleasing manner or style.
4. Archaic Good fortune.
[Middle English felicite, from Old French felicite, from Latin fēlīcitās, from fēlīx, fēlīc-, fortunate; see dhē(i)- in the Appendix of Indo-European roots.]