Zetta- Zetta- Zetta is a decimal unit prefix in the metric system denoting a factor of 10 or . The prefix was added as an SI prefix to the International System of Units (SI) in 1991 and has the symbol Z. Zetta is evocative of the Latin numeral , meaning "seven". Therefore it was used to denote the seventh power of 1000. A prefix of the same value, "hepta", was informally introduced a few years before the promulgation of zetta. It was formed from the Greek (), also meaning "seven". "Hepta" never received official sanction and is obsolete. Zeta (), although
Orders of magnitude (numbers) kilo- (k) (; one hundred thousand or a lakh). ISO: mega- (M) ISO: giga- (G) ISO: tera- (T) ISO: peta- (P) ISO: exa- (E) ISO: zetta- (Z) ISO: yotta- (Y) Orders of magnitude (numbers) This list contains selected positive numbers in increasing order, including counts of things, dimensionless quantity and probabilities. Each number is given a name in the short scale, which is used in English-speaking countries, as well as a name in the long scale, which is used in some of the countries that do not have English as their national language. ISO: yocto- (y) ISO: zepto- (z) ISO: