A "zetta" is a unit of measurement in the International System of Units (SI) that represents one sextillion, or 10^21. It is commonly used to quantify large amounts of data, such as in computing and telecommunications. For example, one zettabyte (ZB) equals one billion terabytes (TB), highlighting the vast scale of data storage. The prefix "zetta" is derived from the Latin word "septem," meaning seven, as it denotes the seventh power of ten in the SI system. Other related prefixes include yotta for 10^24 and exa for 10^18, which are also used to describe large quantities in various scientific fields.