Webster's Revised Unabridged Dictionary · 1913

obsecration

obsecration (ob`se*krā"shun) , noun

[Latin obsecratio: compare French obsecration.]

1.
The act of obsecrating or imploring; as, the obsecrations of the Litany, being those clauses beginning with “By.” — Bp. Stillingfeet
2.
(Rhetoric) A figure of speech in which the orator implores the assistance of God or man.