##### Wiktionary

**yotta-**

pre. In the International System of Units and other metric systems of units, multiplying the unit to which it is attached by 10^{24}. Symbol: Y

##### Wikipedia

**Yotta-**

**Yotta** is the largest decimal unit prefix in the metric system, denoting a factor of 10 or ; that is, one million million million million, or one billion billion (long scale) or, one quadrillion. It has the unit symbol **Y**. The prefix name is derived from the Ancient Greek , meaning "eight", because it is equal to 1,000. It was added as an SI prefix to the International System of Units (SI) in 1991.

Usage examples:

- The mass of the Earth is 5,972.6 Yg.
- The mass of the oceans is about 1.4 Yg.
- The total power output of the Sun is approximately 385 YW.
- The observable universe is estimated to be 880 Ym in diameter.
- 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 1,024 bytes, which is approximately 1.2 septillion bytes.