The term SEDER PROPHET is composed of two words, SEDER and PROPHET. The first word, SEDER, is a Jewish ritual feast that marks the beginning of the Passover holiday. The second word, PROPHET, refers to a person who speaks on behalf of God or a deity, often predicting future events. In this context, the crossword solution ELIJAH (6 letters) is referring to the Hebrew PROPHET Elijah, who is traditionally believed to appear at the Passover Seder to fulfill the role of a messenger from God.