Final answer:
The word 'Pannychis' in the context of the Eleusinian mysteries refers to an all-night vigil or ceremony held in honor of Demeter and Persephone.
Step-by-step explanation:
The word 'Pannychis' in the context of the Eleusinian mysteries refers to an all-night vigil or ceremony held in honor of Demeter and Persephone. The Eleusinian mysteries were ancient religious rituals held in Eleusis, a town near Athens, Greece, dedicated to these two goddesses. During the Pannychis, the initiates would partake in various rites and rituals, including the reenactment of the myth of Demeter and Persephone. This all-night vigil was a significant and highly anticipated event in the Eleusinian Mysteries.