zeta

noun2

1. •
   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)
2. •
   A mathematical function, formally known as the Riemann zeta function.

   • Zeta of 3 is irrational

noun1

1. •
   A member of Los Zetas, a Mexican criminal syndicate.