Definitions
from The American Heritage® Dictionary of the English Language, 4th Edition
 n. The sixth letter of the Greek alphabet. See Table at alphabet.
from Wiktionary, Creative Commons Attribution/ShareAlike License
 n. The name of the sixth letter of the modern Greek alphabet (Ζ, ζ) preceded by epsilon (Ε, ε) and followed by eta, (Η, η); or the seventh letter in the ancient Greek alphabet, in which it is preceded by digamma (Ϝ, ϝ)
 n. A mathematical function formally known as the Riemann zeta function.
from the GNU version of the Collaborative International Dictionary of English
 n. A Greek letter [ζ] corresponding to our z.
from The Century Dictionary and Cyclopedia
 n. The sixth letter of the Greek alphabet, corresponding to the English Z.
 n. Zu + Zv − Z (u + v) = ksn u. sn verb sn (u + v).
 n. A little closet or chamber: applied by some writers to the room over the porch of a Christian church where the porter or sexton lived and kept the church documents.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
 n. the 6th letter of the Greek alphabet
Etymologies
Examples

Riemann had found one very special imaginary landscape, generated by something called the zeta function, which he discovered held the secret to prime numbers.

For the prefix challenged, a zeta is a thousand exas.

He realized that he could use something called the zeta function to build a landscape where the peaks and troughs in a threedimensional graph correspond to the outputs of the function.

In analytic number theory, a multiplicative version of the FourierLaplace transform is often used, namely the zeta function, can be expressed neatly in terms of Mellin transforms. of complex numbers to a formal Laurent series then this becomes a (formal) Fourier series expansion on the unit circle.

Well, that may be true of some of the more general zeta functions (like Ihara), but this article is about Riemann's zeta, which is.

I then looked up and said, "I guess I'll call you 'zeta' now."

Better would be to link them to infinite series, in case, say, they just heard about some famous problem called the "Riemann Hypothesis" involving something called "zeta", but they haven't encountered infinite series before they reach the page.

Rcd3 (CG8231) is homologous to the human Tcomplex protein 1 subunit zeta, which is needed for proper tubulin folding [

"zeta", but they haven't encountered infinite series before they reach the page.

It's designed to make the 14 year old zeta male in you go, Coooooool!
ruzuzu commented on the word zeta
"3. Zu + Zv − Z (u + v) = ksn u. sn verb sn (u + v)."
Cent. Dict.
September 6, 2011
madmouth commented on the word zeta
also an old nation in (roughly) presentday Montenegro.
May 4, 2009