Dragonball Z is the second work in the Dragonball series. It was adapted from the Dragonball manga created by Toriyama Akira, a famous Japanese cartoonist. It first appeared on the television in 19th, April, 1989.
The Dragonball Z story was adapted from chapter 195 to chapter 519 in the manga. TOEI ANIMATION company decided to adapted it into a cartoon movie with the transformation of Toriyama Akria's drawing.
The letter Z in the title was decided by Toriyama Akria. Z is the last letter in the alphabet. Therefore, it also means end.