ep·opt \ˈeˌpäpt\noun (-s) Etymology: Greek epoptēs, literally, overseer, watcher, from epopteuein to watch, supervise, be admitted to the highest grade of the Eleusinian mysteries, from epi- + opteuein to see 1.plural alsoepop·tae\eˈpäpˌtē\orepop·tai\eˈpäpˌtī\: an initiate in the highest grade of the Eleusinian mysteries 2.: one instructed in a secret system