- For other uses, see Nu.
Nu (uppercase Ν, lowercase ν) is the 13th letter of the Greek alphabet. In the system of Greek numerals it has a value of 50. Its Latin Alphabet equivalent is N. The word nu is written νῦ in traditional Greek polytonic orthography. In Modern Greek it is sometimes written νι (ni). In English, either version is pronounced /ˈnuː/ or /ˈnjuː/ (like the English word new). The lower-case letter ν is used as a symbol for:
- The frequency of a wave in physics and other fields.
- Kinematic viscosity in fluid mechanics
- Poisson's ratio, the ratio of strains perpendicular with and parallel with an applied force.
- Specific volume, the volume occupied by a unit of mass of a material.
- Any of three kinds of neutrino in particle physics.
- One of the Greeks in mathematical finance, known as “vega”.
- The number of neutrons released per fission of an atom in nuclear physics.
- A DNA polymerase found in higher eukaryotes and implicated in Translesion Synthesis.
- Molecular vibrational mode, νx where x is the number of the vibration (a label)
