Exordium
Exordium (-um) , noun
[Latin from exordiri to begin a web, lay a warp, begin; ex out + ordiri to begin a web, begin; akin to English order. See Order.]
A beginning; an introduction; especially, the introductory part of a discourse or written composition, which prepares the audience for the main subject; the opening part of an oration.
The exordium of repentance.
Long prefaces and exordiums.