Upsilon

Upsilon (Template:IPAc-en, Template:IPAc-en;Template:RefnTemplate:RefnTemplate:Refn uppercase Υ, lowercase υ; Template:Langx ýpsilon ) or ypsilon Template:IPAc-en is the twentieth letter of the Greek alphabet. In the system of Greek numerals, Template:Langx has a value of 400. It is derived from the Phoenician waw File:Phoenician waw.svg.

File:NAMA Alphabet grec.jpg

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

Etymology

The name of the letter was originally just (, also called , hence hyoid, meaning 'shaped like the letter '), but the name changed to (= , 'u-plain' or 'u-simple') to distinguish it from , which had come to have the same pronunciation.

Pronunciation

In early Attic Greek (6th century BCE), it was pronounced Template:IPAblink (a close back rounded vowel like the English "long o͞o"). In Classical Greek, it was pronounced Template:IPAblink (a close front rounded vowel), at least until 1030. In Modern Greek, it is pronounced ; in the digraphs and , as or ; and in the digraph as . 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

File:Y-like European letters.svg

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

The use 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 or . 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 (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: U, Y and, much later, V and W. In the Cyrillic script, the letters U (У, у) and (Ѵ, ѵ) arose from it.

In some languages, including German and Portuguese, the name upsilon ( in German, 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" ( in Spanish, in French), also noting its Greek origin.

Usage

• In particle physics the capital Greek letter ϒ denotes an Upsilon particle. Note that the symbol should always look like $\mathrm{{\rm Y}}$ 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.
• In the International Phonetic Alphabet, the symbol Template:Angbr IPA is used to represent a labiodental approximant.
• In astrophysics and physical cosmology, ϒ refers to the mass-to-light ratio.
• In statistics, it is sometimes used instead of v or nu to indicate degrees of freedom.
• In the Persian language, “one upsilon” is used to describe a positive amount close to 0 (zero).

Similar appearance

• A similar symbol Template:Unichar is used for the astrological sign of Aries.

Symbolism

File:Geoffrey Tory Ypsilon.jpg

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. As the Roman writer Persius wrote in Satire III: Template:Quote Lactantius, an early Christian author (ca. 240 – ca. 320), refers to this: Template:Quote

Character encodings

Upsilon and Coptic Ua characters.

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