Upsilon

Twentieth letter in the Greek alphabet

Not to be confused with Epsilon.

This article is about the Greek upsilon. For the Latin upsilon, see ʊ. For other uses, see Upsilon (disambiguation).

"Ypsilon" redirects here. For other uses, see Ypsilon (disambiguation).

Greek alphabet
|  Αα|  Alpha|  Νν|  Nu

|
|
|

Ββ|  Beta|  Ξξ|  Xi
Γγ|  Gamma|  Οο|  Omicron
Δδ|  Delta|  Ππ|  Pi
Εε|  Epsilon|  Ρρ|  Rho
Ζζ|  Zeta|  Σσς|  Sigma
Ηη|  Eta|  Ττ|  Tau
Θθ|  Theta|  Υυ|  Upsilon
Ιι|  Iota|  Φφ|  Phi
Κκ|  Kappa|  Χχ|  Chi
Λλ|  Lambda|  Ψψ|  Psi
Μμ|  Mu|  Ωω|  Omega
History

Archaic local variants

* Ϝ
* Ͱ
* Ϻ
* Ϙ
* Ͳ
* Ͷ

* tsan
* digamma

* Diacritics
* Ligatures

Numerals

* ϛ (6)
* ϟ (90)
* ϡ (900)

Use in other languages

* Bactrian
* Coptic
* Albanian

Related topics

* Use as scientific symbols

* Category

* v
* t
* e

Upsilon (/ˈʌpsɪˌlɒn, ˈ(j)uːp-, -lən/, UK also /(j)uːpˈsaɪlən, ʊp-, -lɒn/;[1][2][3][4][5][6] uppercase Υ, lowercase υ; Greek: ύψιλον ýpsilon [ˈipsilon]) or ypsilon /ɪp-/[1] is the twentieth letter of the Greek alphabet. In the system of Greek numerals, Υʹ has a value of 400. It is derived from the Phoenician waw .

The Greek alphabet on a black figure vessel, with a V-shaped upsilon

## Etymology[edit]

The name of the letter was originally just "υ" (y; also called hy, hence "hyoid", meaning "shaped like the letter υ"), but the name changed to "υ ψιλόν" u psilon 'simple u' to distinguish it from οι, which had come to have the same [y] pronunciation.[7]

## Pronunciation[edit]

In early Attic Greek (6th century BCE), it was pronounced [u] (a close back rounded vowel like the English "long o͞o").[8][9] In Classical Greek, it was pronounced [y] (a close front rounded vowel), at least until 1030.[10] In Modern Greek, it is pronounced [i]; in the digraphs αυ and ευ, as [f] or [v]; and in the digraph ου as [u]. In ancient Greek, it occurred in both long and short versions, but Modern Greek does not have a length distinction.

As an initial letter in Classical Greek, it always carried the rough breathing (equivalent to h) as reflected in the many Greek-derived English words, such as those that begin with hyper- and hypo-. This rough breathing was derived from an older pronunciation that used a sibilant instead; this sibilant was not lost in Latin, giving rise to such cognates as super- (for hyper-) and sub- (for hypo-).

Upsilon participated as the second element in falling diphthongs, which have subsequently developed in various ways.

## Correspondence with Latin Y[edit]

Cyrillic У, Latin Y and Greek Υ and ϒ in FreeSerif – one of the few typefaces that distinguish between the Latin and the Greek form

The usage of Y in Latin dates back to the first century BC. It was used to transcribe loanwords from Greek, so it was not a native sound of Latin and was usually pronounced /u/ or /i/. The latter pronunciation was the most common in the Classical period and was used mostly by uneducated people. The Roman Emperor Claudius proposed introducing a new letter into the Latin alphabet to transcribe the so-called sonus medius (a short vowel before labial consonants), but in inscriptions, the new letter was sometimes used for Greek upsilon instead.

Four letters of the Latin alphabet arose from it: and U , Y and, much later, V and W. In the Cyrillic script, the letters U (У, у) and izhitsa (Ѵ, ѵ) arose from it.

In some languages, including German and Portuguese, the name upsilon (Ypsilon in German, ípsilon in Portuguese) is used to refer to the Latin letter Y as well as the Greek letter. In some other languages, the (Latin) Y is referred to as a "Greek I" (i griega in Spanish, i grec in French), also noting its Greek origin.

## Usage[edit]

* In particle physics the capital Greek letter ϒ denotes an Upsilon particle. Note that the symbol should always look like  Υ {\displaystyle \,\Upsilon } in order to avoid confusion with a Latin Y denoting the hypercharge. This may be done either with a font such as FreeSerif or with the dedicated Unicode character U+03D2 ϒ.
* Automobile manufacturer Lancia has a model called the Ypsilon. See Lancia Ypsilon.
* In the International Phonetic Alphabet, the symbol ⟨ʋ⟩ is used to represent a labiodental approximant.
* In astrophysics and physical cosmology, ϒ refers to the mass-to-light ratio.[11]
* In statistics, it is sometimes used instead of v or nu to indicate degrees of freedom[12]

### Similar appearance[edit]

* A similar symbol  (Unicode ♈ U+2648) is used for the astrological sign of Aries.

## Symbolism[edit]

Geoffroy Tory Ypsilon

Upsilon is known as Pythagoras' letter, or the Samian letter, because Pythagoras used it as an emblem of the path of virtue or vice.[13] As the Roman writer Persius wrote in Satire III:

> and the letter which spreads out into Pythagorean branches has pointed out to you the steep path which rises on the right.[14]

Lactantius, an early Christian author (ca. 240 – ca. 320), refers to this:

> For they say that the course of human life resembles the letter Y, because every one of men, when he has reached the threshold of early youth, and has arrived at the place "where the way divides itself into two parts," is in doubt, and hesitates, and does not know to which side he should rather turn himself.[15]

## Character encodings[edit]

* Greek Upsilon

Character information  Preview | Υ | υ | ϒ

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|
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Unicode name  | GREEK CAPITAL LETTER UPSILON  | GREEK SMALL LETTER UPSILON  | GREEK UPSILON WITH HOOK SYMBOL
Encodings | decimal | hex | dec | hex | dec | hex
Unicode | 933 | U+03A5 | 965 | U+03C5 | 978 | U+03D2
UTF-8 | 206 165 | CE A5 | 207 133 | CF 85 | 207 146 | CF 92
Numeric character reference | &#933; | &#x3A5; | &#965; | &#x3C5; | &#978; | &#x3D2;
Named character reference | &Upsilon; | &upsi;, &upsilon; | &Upsi;, &upsih;
DOS Greek | 148 | 94 | 172 | AC |  |
DOS Greek-2 | 209 | D1 | 239 | EF |  |
Windows 1253 | 213 | D5 | 245 | F5 |  |
TeX | \Upsilon | \upsilon |

[16]

* Coptic Ua

Character information  Preview | Ⲩ | ⲩ

|
|

Unicode name  | COPTIC CAPITAL LETTER UA  | COPTIC SMALL LETTER UA
Encodings | decimal | hex | dec | hex
Unicode | 11432 | U+2CA8 | 11433 | U+2CA9
UTF-8 | 226 178 168 | E2 B2 A8 | 226 178 169 | E2 B2 A9
Numeric character reference | &#11432; | &#x2CA8; | &#11433; | &#x2CA9;

* Latin Upsilon

Character information  Preview | Ʊ | ʊ | ᶷ | ᵿ

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Unicode name  | LATIN CAPITAL LETTER UPSILON  | LATIN SMALL LETTER UPSILON  | MODIFIER LETTER SMALL UPSILON  | LATIN SMALL LETTER UPSILON WITH STROKE
Encodings | decimal | hex | dec | hex | dec | hex | dec | hex
Unicode | 433 | U+01B1 | 650 | U+028A | 7607 | U+1DB7 | 7551 | U+1D7F
UTF-8 | 198 177 | C6 B1 | 202 138 | CA 8A | 225 182 183 | E1 B6 B7 | 225 181 191 | E1 B5 BF
Numeric character reference | &#433; | &#x1B1; | &#650; | &#x28A; | &#7607; | &#x1DB7; | &#7551; | &#x1D7F;

* Mathematical Upsilon

Character information  Preview | 𝚼 | 𝛖 | 𝛶 | 𝜐 | 𝜰 | 𝝊

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Unicode name  | MATHEMATICAL BOLD
CAPITAL UPSILON  | MATHEMATICAL BOLD
SMALL UPSILON  | MATHEMATICAL ITALIC
CAPITAL UPSILON  | MATHEMATICAL ITALIC
SMALL UPSILON  | MATHEMATICAL BOLD ITALIC
CAPITAL UPSILON  | MATHEMATICAL BOLD ITALIC
SMALL UPSILON
Encodings | decimal | hex | dec | hex | dec | hex | dec | hex | dec | hex | dec | hex
Unicode | 120508 | U+1D6BC | 120534 | U+1D6D6 | 120566 | U+1D6F6 | 120592 | U+1D710 | 120624 | U+1D730 | 120650 | U+1D74A
UTF-8 | 240 157 154 188 | F0 9D 9A BC | 240 157 155 150 | F0 9D 9B 96 | 240 157 155 182 | F0 9D 9B B6 | 240 157 156 144 | F0 9D 9C 90 | 240 157 156 176 | F0 9D 9C B0 | 240 157 157 138 | F0 9D 9D 8A
UTF-16 | 55349 57020 | D835 DEBC | 55349 57046 | D835 DED6 | 55349 57078 | D835 DEF6 | 55349 57104 | D835 DF10 | 55349 57136 | D835 DF30 | 55349 57162 | D835 DF4A
Numeric character reference | &#120508; | &#x1D6BC; | &#120534; | &#x1D6D6; | &#120566; | &#x1D6F6; | &#120592; | &#x1D710; | &#120624; | &#x1D730; | &#120650; | &#x1D74A;

Character information  Preview | 𝝪 | 𝞄 | 𝞤 | 𝞾

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|
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Unicode name  | MATHEMATICAL SANS-SERIF
BOLD CAPITAL UPSILON  | MATHEMATICAL SANS-SERIF
BOLD SMALL UPSILON  | MATHEMATICAL SANS-SERIF
BOLD ITALIC CAPITAL UPSILON  | MATHEMATICAL SANS-SERIF
BOLD ITALIC SMALL UPSILON
Encodings | decimal | hex | dec | hex | dec | hex | dec | hex
Unicode | 120682 | U+1D76A | 120708 | U+1D784 | 120740 | U+1D7A4 | 120766 | U+1D7BE
UTF-8 | 240 157 157 170 | F0 9D 9D AA | 240 157 158 132 | F0 9D 9E 84 | 240 157 158 164 | F0 9D 9E A4 | 240 157 158 190 | F0 9D 9E BE
UTF-16 | 55349 57194 | D835 DF6A | 55349 57220 | D835 DF84 | 55349 57252 | D835 DFA4 | 55349 57278 | D835 DFBE
Numeric character reference | &#120682; | &#x1D76A; | &#120708; | &#x1D784; | &#120740; | &#x1D7A4; | &#120766; | &#x1D7BE;

These characters are used only as mathematical symbols. Stylized Greek text should be encoded using the normal Greek letters, with markup and formatting to indicate text style.

## Notes[edit]

1. ^ a b "upsilon". Chambers Dictionary (9th ed.). Chambers. 2003. ISBN 0-550-10105-5.
2. ^ "upsilon". Collins English Dictionary (13th ed.). HarperCollins. 2018. ISBN 978-0-008-28437-4.
3. ^ "Upsilon". Merriam-Webster.com Dictionary. Retrieved 2016-01-22.
4. ^ "Upsilon". Lexico UK English Dictionary. Oxford University Press. Archived from the original on 2019-12-21.
5. ^ "upsilon". Dictionary.com Unabridged (Online). n.d. Retrieved 2016-01-22.
6. ^ "upsilon". Oxford English Dictionary (Online ed.). Oxford University Press. (Subscription or participating institution membership required.)
7. ^ W. Sidney Allen, Vox Graeca, 3rd ed., Cambridge 1987, p. 69.
8. ^ Woodard, Roger D. (June 12, 1997). Greek Writing from Knossos to Homer: A Linguistic Interpretation of the Origin of the Greek Alphabet and the Continuity of Ancient Greek Literacy. Oxford University Press. ISBN 9780195355666 - via Google Books.
9. ^ Mastronarde, Donald J. (February 21, 2013). Introduction to Attic Greek. University of California Press. ISBN 9780520275713 - via Google Books.
10. ^ F. Lauritzen, "Michael the Grammarian's irony about Hypsilon. A step towards reconstructing Byzantine pronunciation", Byzantinoslavica, 67 (2009)
11. ^ Mihalas and McRae (1968), Galactic Astronomy (W. H. Freeman)
12. ^ Walpole, Ronald (2017). Probability and Statistics for Scientists and Engineers (9th ed.).
13. ^ Brewer, Ebenezer Cobham. The reader's handbook of famous names in fiction, allusions, references, proverbs, plots, stories, and poems, Vol. 2, p. 956. Lippincott, 1899.
14. ^ Persius (1920). Satires.
15. ^ Lactatius. The Divine Institutes. pp. Book VI Chapter III.
16. ^ Unicode Code Charts: Greek and Coptic (Range: 0370-03FF)

## External links[edit]

Look up Υ or υ in Wiktionary, the free dictionary.

Wikimedia Commons has media related to Upsilon (letter).

* Merrifield, Michael (2009). "Υ – Mass to Light Ratio". Sixty Symbols. Brady Haran for the University of Nottingham.

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