zeta

noun

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”

3. A member of Los Zetas, a Mexican criminal syndicate.

name

1. (historical)medieval state roughly equivalent to modern Montenegro.
2. (abbreviation, acronym, alt-of)Acronym of zero-energy thermonuclear assembly/apparatus (“a torus-shaped reactor used in the mid-20th century to carry out experiments in plasma physics and temperature-controlled thermonuclear reactions”).