The eleventh Greek letter, used for wavelength, eigenvalues and anonymous functions.
Also known as: Greek letter lambda, Lambda symbol, Wavelength symbol, λ
Lambda is one of the most heavily overloaded letters in science: wavelength in optics, eigenvalue in linear algebra, decay constant in nuclear physics, rate in statistics, and anonymous function in computing. The field decides, and nothing else does.
Is a letter of the Greek alphabet before it is a symbol: what it denotes is fixed by the field it appears in, not by the character itself. The uses below are the documented conventions, not competing definitions.
Contexts: Mathematics
In optics and wave physics, denotes wavelength — the distance between successive peaks.
Contexts: Mathematics
In linear algebra, denotes an eigenvalue of a matrix.
Contexts: Mathematics
In nuclear physics, denotes the decay constant of a radioactive isotope.
Contexts: Mathematics
In statistics, denotes the rate parameter of a Poisson distribution.
Contexts: Mathematics
In computing, denotes an anonymous function, from Church's lambda calculus.
Contexts: Mathematics
Is the clearest case in the alphabet of a letter with no meaning of its own: five unrelated fields use it for five unrelated quantities, and only the context distinguishes them.
Contexts: Mathematics
Two straight strokes meeting near the top, the left one short and the right one descending further, like an upside-down V with an extended tail.
The same character recorded twice: once as a Greek letter, once as the physical quantity it most often denotes.
Wavelength and angular frequency describe the same wave from different ends, and are related by a fixed formula.