IPA: /ˌɛpɪˈtæsɪs/
KK: /ɛˈpɪtəsɪs/
The central section of a play where the main events unfold and build up to the climax or disaster.
In the epitasis of the play, the tension between the characters reaches its peak.
Epitasis is derived from the Greek word "epitasis" (ἐπίτασις), which is formed from "epi-" (meaning upon or in addition) and "tasis" (meaning stretching or tension). The term originally referred to the part of a play where the action intensifies, thus conveying the idea of an added tension or development in the narrative.
Think of 'upon' ('epi-') adding 'tension' ('tasis') to a story — that's why epitasis refers to the part of a play where the action intensifies.