Zeta (letter)

Zeta (upper case Ζ, lower case ζ) is the sixth letter of the Greek alphabet. In the system of Greek numerals it has a value of 7.

The lower-case letter ζ is used as symbol for:

• The Riemann zeta function and other zeta functions in mathematics.
• In polymer dynamics, the coefficient of viscous friction.
• In astronomy, the sixth brightest (usually) star in a constellation. See Bayer designation.

Letters related to Zeta include the Roman Z.

See also Z (movie).