For the longest time, fans never knew what Androids 17 and 18’s real names were. It’s been established they were both humans before Dr. Gero kidnapped them and turned them into artificial humans, yet they continued going by the numbers that the evil doctor gave them even after 17 murders him. Their backstory and true names remained a mystery to fans for years, until 2014 when Toriyama finally unveiled the character’s true names.
It turns out 17’s real name is Lapis, and 18’s name is Lazuli. “Lapis Lazuli” is the name of a rare blue stone. The ancient meaning of “Lapis” and “Lazuli” originates from the Latin and Persian spellings for “stone” and “blue” respectively. It is unknown why 17 and 18 do not go by their original human names and continue to use the numbers given to them by a madman who experimented on them with no consent.