Zenzizenzizenzic is an obsolete form of mathematical notation representing the eighth power of a number (that is, the zenzizenzizenzic of a number x is the power x8), dating from a time when powers were written out in words rather than as superscript numbers. This term was suggested by Robert Recorde, a 16th-century Welsh writer of popular mathematics textbooks, in his 1557 work The Whetstone of Witte (although his spelling was zenzizenzizenzike); he wrote that it "doeth represent the square of squares squaredly".
At the time Recorde proposed this notation, there was no easy way of denoting the powers of numbers other than squares and cubes. The root word for Recorde's notation is zenzic, which is a German spelling of the medieval Italian word censo, meaning "squared". Since the square of a square of a number is its fourth power, Recorde used the word zenzizenzic (spelled by him as zenzizenzike) to express it. Some of the terms had prior use in Latin "zenzicubicus", "zensizensicus" and "zensizenzum". This is a condensed form of the Italian censo di censo, used by Leonardo of Pisa in his famous book Liber Abaci of 1202. Similarly, as the sixth power of a number is equal to the square of its cube, Recorde used the word zenzicubike to express it; a more modern spelling, zenzicube, is found in Samuel Jeake's Logisticelogia. Finally, the word zenzizenzizenzic denotes the square of the square of a number's square, which is its eighth power: in modern notation,
Recorde proposed three mathematical terms by which any power (that is, index or exponent) greater than 1 could be expressed: zenzic, i.e. squared; cubic; and sursolid, i.e. raised to a prime number greater than three, the smallest of which is five. Sursolids were as follows: 5 was the first; 7, the second; 11, the third; 13, the fourth; etc.
Therefore, a number raised to the power of six would be zenzicubic, a number raised to the power of seven would be the second sursolid, hence bissursolid (not a multiple of two and three), a number raised to the twelfth power would be the "zenzizenzicubic" and a number raised to the power of ten would be the square of the (first) sursolid. The fourteenth power was the square of the second sursolid, and the twenty-second was the square of the third sursolid.
The word, as well as the system, is obsolete except as a curiosity; the Oxford English Dictionary has only one citation for it. As well as being a mathematical oddity, it survives as a linguistic oddity: zenzizenzizenzic has more Zs than any other word in the OED.
Jeake however gives zenzizenzizenzizenzike in a table in A compleat body of arithmetic...
|Indices||Characters||Signification of the Characters|
|0||N||An Absolute Number, as if it had no Mark|
|16||ℨℨℨℨ||A Zenzizenzizenzizenzike or Square of Squares Squaredly Squared|
- Quinion, Michael, "Zenzizenzizenzic - the eighth power of a number", World Wide Words, retrieved 2010-03-19.
- Michael Stifel. Arithmetica Integra (in Latin). Nuremburg. p. 61.
- Knight (1868).
- Reilly (2003).
- "Recorde also coined zenzizenzizenzic, the word in the Oxford English Dictionary (OED) with more Zs than any other" (Reilly 2003).
- Uniquely contains six Z 's. Thus, it's the only hexazetic word in the English language. "Numerical Adjectives, Greek and Latin Number Prefixes". phrontistery.info. Retrieved 19 March 2010.
- Jeake, S. (1701). In Jeake, S. A compleat body of arithmetic, in four books: Wherein the whole nature of numbers, with their simple and comparative elements in all the parts of arithmetick, are plainly declared, and fully handled. Every part explain'd by necessary rules, cases, theorems, questions, observations, and variety of operations ... To every part is added, excellent rules of practice ... With many large and exact tables of all sorts of coins, weights, measures, &c. ancient and modern, in most countries, reduced to our own. London: Printed for T. Newborough [etc...
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- Reilly, Edwin D. (2003), Milestones in Computer Science and Information Technology, Greenwood Publishing Group, p. 3, ISBN 978-1-57356-521-9.
- Todd, Richard Watson (2006), Much Ado About English, Nicholas Brealey Publishing, ISBN 978-1-85788-372-5.
- Uldrich, Jack (2008), "Chapter 2. The Power of Zenzizenzizenzic", Jump the Curve: 50 Essential Strategies to Help Your Company Stay Ahead of Emerging Technologies, Adams Media, ISBN 978-1-59869-420-8.