What does genki (from genki dama) means?
http://dragonball.wikia.com/wiki/Spirit_Bomb:


  Spirit Bomb (元気玉 Genki Dama, lit. "Energy Sphere")


https://en.wiktionary.org/wiki/元氣


  From Middle Chinese compound 元氣 (ngjwon khjɨjH, literally “first, fundamental, source + vapor, spirit, energy”) In Chinese cosmology, this represented the fundamental force that permeates all matter and life. Early Japanese borrowed this word and meaning. Later, this spelling was conflated with the meaning of homophone 減気 (genki, “recovery from illness”), adding in the modern senses related to healthy and wellness.