Lewis & Short

obsĕcrātĭo, ōnis, f. [obsecro].

  1. I. In gen., a beseeching, imploring, supplication, entreaty (class.): prece et obsecratione humili uti, Cic. Inv. 1, 16, 22; id. Font. 17, 39: judicum, addressed to the judges, Quint. 6, 1, 33: percipe obsecrationem meam, Vulg. Psa. 142, 1: fit ad Deum pro illis, id. Rom. 10, 1.
  2. II. In partic.
    1. A. An asseveration, protestation, accompanied by an invocation of the gods or of religious things, Gr. δέησις, Cic. de Or. 3, 53, 105; cf. Just. 24, 2, 5; cf. Macr. S. 1, 6, 13.
    2. B. A public prayer: obsecrationem indicere, Liv. 27, 11; id. 4, 21; 26, 23; 31, 9; Cic. Har. Resp. 28 fin.: habere, Suet. Caes. 22.