Meanings
- informalSynonym of ronna- (used before an official prefix existed). Symbol: X
But that's nothing: our universe is about 0.8 Xm (Xennametres, billions of billions of billions of metres) in diameter.
2015, Claude Phipps, No Wonder You Wonder!: Great Inventions and Scientific Mysteries, Springer, page 622 more examples
The SI prefixes above are not the only extreme ones. Others such as xenno (x) (10⁻²⁷) and xenna (X) (10²⁷), or vendeko (v) (10⁻³³) and vendeka (V) (10³³) exist, and can help simplify the expression of extreme numbers.
1994, IPC Magazines, New Scientist, volume 144, page 81If we try to calculate the mass of earth it comes to 6 xennagrams which is nothing but 6x10²⁴ kilograms or 6x10²⁷ gms.
1997, Council of Scientific & Industrial Research, Science Reporter, volume 34, page 23Synonyms: ronna-
Synonyms & antonyms
prefixSynonym of ronna- (used before an official prefix existed). Symbol: X
Origin
- Ancient Greekἐννέα“nine”
- Englishxenna-
From Ancient Greek ἐννέα (ennéa, “nine”), for the ninth order of 10³, and the letter x, as the third term in a series running backwards through the alphabet (after zetta- and yotta-). The final a conforms to the final vowel of the SI series from mega- upwards.
More words from Ancient Greek
Full word history & related roots →Cite this entry
xenna-. (n.d.). In WatkinsX Dictionary. Retrieved November 3, 2026, from https://dictionary.watkinsx.com/word/xenna-
“xenna-.” WatkinsX Dictionary, https://dictionary.watkinsx.com/word/xenna-. Accessed November 3, 2026.
WatkinsX Dictionary, s.v. “xenna-,” accessed November 3, 2026, https://dictionary.watkinsx.com/word/xenna-.
Source: xenna- on Wiktionary, CC BY-SA 4.0.