nu (letter)
{{Short description|Thirteenth letter in the Greek alphabet}}
{{Other uses|Nu (disambiguation)}}
{{Dist|Mu (letter)|N|En (Cyrillic)|v}}
{{Greek Alphabet|letter=nu}}
Nu, or ny ({{IPAc-en|'|n|j|uː|audio=LL-Q1860 (eng)-Flame, not lame-Nu.wav}}; uppercase Ν, lowercase ν; {{langx|el|vι}} ni {{IPA|el|ni|}}), is the thirteenth letter of the Greek alphabet, representing the voiced alveolar nasal {{IPA|el|n|IPA}}. In the system of Greek numerals it has a value of 50. It is derived from the Phoenician nun 20px. Its Latin equivalent is N, though the lowercase () resembles the Roman lowercase v.
The name of the letter is written {{lang|grc|νῦ}} in Ancient Greek and traditional Modern Greek polytonic orthography, while in Modern Greek it is written {{lang|el|νι}} {{IPA|[ni]}}.
Letters that arose from nu include Roman N and Cyrillic script En.
Symbology
File:Nikos_Kazantzakis_Statue_in_Heraklion.jpg with the traditional Greek nu]]
The lower-case letter {{mvar|ν}} is used as a symbol in many academic fields. Uppercase nu is not used, because it appears identical to Latin N.
- Mathematics:
- Degrees of freedom in statistics.
- The greatest fixed point of a function, as commonly used in the μ-calculus.
- Free names of a process, as used in the π-calculus.
- One of the Greeks in mathematical finance, known as "vega".
- The reciprocal of 1 plus the interest rate in finance.
- The p-adic valuation of a number.
- Physics:
- Kinematic viscosity in fluid mechanics.{{Citation |last=Elert |first=Glenn |title=Special Symbols |date=2023 |work=The Physics Hypertextbook |url=https://physics.info/symbols/ |access-date=2025-02-01 |publisher=hypertextbook|quote= ν kinematic viscosity |language=en}}
- The frequencySee e.g. Planck's formula of a wave in physics and other fields; sometimes also spatial frequency; wavenumber
- The specific volume in thermodynamics.
- Poisson's ratio, the ratio of strains perpendicular with and parallel with an applied force.
- Any of three kinds of neutrino in particle physics.
- The number of neutrons released per fission of an atom in nuclear physics.
- Molecular vibrational mode, {{math|νx}} where {{mvar|x}} is the number of the vibration (a label).
- The true anomaly, an angular parameter that defines the position of a body moving along an orbit (see orbital elements).
- Biology:
- A DNA polymerase found in higher eukaryotes and implicated in translesion synthesis.
- Chemistry:
- The stoichiometric coefficient.
- Psychology:
- The maximum conditioning possible for an unconditioned stimulus in the Rescorla-Wagner model.
Unicode
Encodings of Greek Nu and Coptic Ni.Unicode Code Charts: [https://www.unicode.org/charts/PDF/U0370.pdf Greek and Coptic (Range: 0370-03FF)]
- {{unichar|039D|html=}}
- {{unichar|03BD|html=}} ({{code|\nu}} in TeX)
- {{unichar|2C9A}}
- {{unichar|2C9B}}
- {{unichar|1D6B4}}{{efn|The {{sc|mathematical}} symbols should only be use for math. Stylized Greek text should be encoded using the normal Greek letters, with markup and formatting to indicate text style.}}
- {{unichar|1D6CE}}
- {{unichar|1D6EE}}
- {{unichar|1D708}}
- {{unichar|1D728}}
- {{unichar|1D742}}
- {{unichar|1D762}}
- {{unichar|1D77C}}
- {{unichar|1D79C}}
- {{unichar|1D7B6}}
{{notelist}}