upsilon

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

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
Obsolete letters
	Digamma		Qoppa
	San		Sampi
Other characters
	Stigma		Sho
	Heta
Greek diacritics

Upsilon (uppercase Υ, lowercase υ; Greek: Ύψιλον, Úpsilon) is the 20th letter of the Greek alphabet. In the system of Greek numerals it has a value of 400. It is derived from the Phoenician waw. The name of the letter is pronounced [ˈipsilon] in Modern Greek, and in English pronounced /ˈʌpsɨlɒn/, UK: /juːpˈsaɪlən/, or US: /ˈjuːpsɨlɒn/. It is rarely called "ypsilon" (/ˈɪpsɨlɒn/) in English because of its resemblance to the Roman letter Y.

Pronunciation

In early Greek it was pronounced like oo IPA: [u] . In Classical Greek, it was pronounced like French u or German ü, IPA: [y]—a sound that is not found in most dialects of English. In Modern Greek it is pronounced like continental i or English ee, IPA: [i], and in diphthongs, [f] or [v]. In ancient Greek it occurred in both long and short versions, but this distinction has been lost in Modern Greek.

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 which 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: for instance after alpha or epsilon it is pronounced [f] or [v].

Correspondence with Latin Y

The usage of Y in Latin dates back to the I 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 by most people except the educated ones. 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 was sometimes used for Greek upsilon instead.

The name of the letter was originally just υ (y; also called hy, hence "hyoid", meaning "y-shaped"). It changed to υ ψιλόν, (u psilon, meaning 'simple u') to distinguish it from οι, which had come to have the same [y] pronunciation.^[1] Four letters of the Latin alphabet arose from it: V and Y and, much later, U and W. In the Cyrillic alphabet, the letters U (У, у) and Izhitsa (Ѵ, ѵ) arose from it.

Usage

• In particle physics the capital Greek letter ϒ denotes an Upsilon particle. Note that the symbol should always look like ϒ in order to avoid confusion with a Latin Y denoting the hypercharge.
• Automobile manufacturer Lancia has a model called the Ypsilon. See Lancia Ypsilon.
• In linguistics, the symbol is used to represent a labiodental approximant.

Notes