Zeta/ˈzeɪtə/ Definition 1 of 5Pro Tip 1/2Greek Origin Remember 'zeta' is Greek, it might refer to Greek culture, language, or history. Studying Greek myths, one must know the alphabet, from alpha to zeta. Pro Tip 2/2Not Just a Letter 'Zeta' can symbolize something in sequence or a certain position like 'Plan Z'. We need to move to plan zeta if the first five fail.