An Etymological Dictionary of Astronomy and Astrophysics

The eleventh letter of the Greek alphabet. In lower case, λ, it denotes → wavelength. It is also used in the → Bayer designation system to identify a specific star in a → constellation. See also → lambda point.

In upper case, Λ, it represents the → cosmological constant or → dark energy.

See also: From Phoenician lamedh.