Look up yotta- in Wiktionary, the free dictionary.
Yotta is the largest decimalunit prefix in the metric system, denoting a factor of 1024 or 1000000000000000000000000; that is, one million million million million, or one septillion. It has the unit symbol Y. The prefix name is derived from the Ancient Greekοκτώ (októ), meaning "eight", because it is equal to 1,0008. It was added as an SI prefix to the International System of Units (SI) in 1991.[1]
One yottabyte (YB) is a unit of digital information or information storage capacity that contains one septillion bytes or 1,000 zettabytes. The yobibyte (YiB) is a related unit that uses a binary prefix, and means 1,0248 bytes, which is approximately 1.2 septillion bytes.