James S. Huggins' Refrigerator Door: Click here to go to my Home Page. kilo, mega, giga, tera, peta, exa, zetta, yotta, kilobyte, megabyte, gigabyte, terabyte, petabyte, exabyte, zettabyte, yottabyte, kilo, mega, giga, tera, peta, exa, zetta, yotta, kilobyte, megabyte, gigabyte, terabyte, petabyte, exabyte, zettabyte, yottabyte, qwerty
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Where Did Kilo, Mega, Giga and All Those Other Prefixes Come From? - - - Photo of the numeral zero, with a blurred 1 in the foreground and 9, 8, 7 blurred in the background - - - Original photo copyright Ed Hidden - - - Licensed through iStockphoto.com
Where Did Kilo, Mega, Giga and All Those Other Prefixes Come From?

They have entered our language. Everyone uses them. The terms, particularly with "byte", are almost commonplace. Kilobyte, Megabyte and Gigabyte are part of our lexicon.

But do you know where they came from?

First, let's show the terms:

Kilo 10001 103 1,000
Mega 10002 106 1,000,000
Giga 10003 109 1,000,000,000
Tera 10004 1012 1,000,000,000,000
Peta 10005 1015 1,000,000,000,000,000
exa 10006 1018 1,000,000,000,000,000,000
Zetta 10007 1021 1,000,000,000,000,000,000,000
Yotta 10008 1024 1,000,000,000,000,000,000,000,000

 

Ok. So where did they come from?

Kilo comes from the Greek khiloi and means, curiously enough, 1000. It is interesting enough, the only prefix with a direct numerical meaning.

The next three come from Greek and Latin and are either descriptive or mythological.

Mega comes from the Greek mega meaning "great", as in "Alexandros O Megas" or "Megas Alexandros" (Alexander the Great).

Giga comes from Latin gigas meaning "giant".

Tera comes from Greek teras meaning "monster".

Now we return to numbers. Though not direct numerical references, the next two are indirect references.

Peta comes from the Greek pente meaning five. This is the fifth prefix (for 10005). This term, and the next one, were both added in 1975 by the General Conference of Weights and Measures (abbreviated CGMP because it is in France)

exa comes from Greek hex meaning six. This is the sixth prefix (for 10006). Taking "Hexa" and making the "H" silent (as it is in France, home of  the CGMP) gives "exa".

Here we leave the numerical references again. Unable to return to the mythological (after great, giants and monsters what else is there), we move to the Latin alphabet. For reasons I don't know, we start with the last letter (Zetta), working backwards to the beginning.

Zetta, often mistaken for the Greek Zeta, is the last letter of the Latin alphabet. This prefix and the next one were added in 1990 by CGMP.

Yotta is the penultimate (next to last) letter of the Latin alphabet.


On My Site

Two or TenTwo or Ten?: Does Kilo mean exactly 1,000 or does it mean 1,024? Think you know? Want to bet? (Two_or_Ten)

 

Across the Web

AttoparsecAttoparsec: So you think you know about all sorts of different measures. Check out this article in The Online Hacker Jargon File (the online equivalent to The New Hacker's Dictionary ) to learn about some measures that have gained cult status.  (www.catb.org/~esr/jargon/html/entry/attoparsec.html)

The Online Hacker Jargon FileThe Online Hacker Jargon File: This link is to the primary resource page for the file. It includes links, not only to the Jargon File itself, but also to downloadable versions, information on quotation, the book version ( The New Hacker's Dictionary ), jargon construction, hacker style, history, making suggestions, etc.  (www.catb.org/~esr/jargon)

The Peta PrincipleThe Peta Principle: This online article by Jim Binder of the San Diego Supercomputer Center was a source for some of the information in this article. (www.sdsc.edu/GatherScatter/gsq394/gsq3_f1.html)

QuantifiersQuantifiers: This entry from The Online Hacker Jargon File (the online equivalent to The New Hacker's Dictionary ) not only discusses Kilo and Mega and Giga and the confusions between powers of two and powers of ten (e.g., does Kilo mean 1,000 or 1,024), but even notes the proposal for groucho and harpo as prefixes.  (www.catb.org/~esr/jargon/html/entry/quantifiers.html)

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This page created:
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Last updated:
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