yotta

An International System of Units (SI, a.k.a. metric) prefix denoting 10 to the 24th power (10e+24 or 10^24). It's symbol is Y.

In other words, Y 's multiplier is 1,000,000,000,000,000,000,000,000 (a.k.a. a septillion).

see also: Standard SI prefixes

Note that 'yotta' now officially means 10²⁴ even in the context of data processing. The prefixes kilo, mega, giga, tera, peta, exa, zetta, yotta always refer to powers of 10.

To refer to powers of 2¹⁰ (powers of 1024), use the new binary prefixes kibi, mebi, gibi, tebi, pebi, and exbi. That is as high as they go; there are no official prefixes 'zebi' or 'yobi'.

These new prefixes were created in December 1998 by the International Electrotechnical Commission: see the node prefixes for binary multiples for fuller explanation.

The prefix 'yotta' was originally adopted by the nineteenth CGPM of the SI in 1991, along with zetta, yocto, and zepto. It comes from an alteration of the Greek for 'eight'.