Lewis & Short

Prorsa (Prōsa), ae, f. [2. prorsus], sc. dea, i. e. the goddess presiding over births with the head foremost (opp. Postverta), Varr. ap. Gell. 16, 16, 4; cf. Hartung, Relig. d. Röm. 2, p. 199.

2. prorsus (collat. form prōsus; v. II.), a, um, adj. [for pro-versus].

  1. I. Straightforwards, right onwards, straight, direct (post-Aug.): prorso tramite siste gradus (al. proso), Avien. 3: prorsi limites appellantur in agrorum mensuris, qui ad orientem directi sunt, Fest. p. 234, and Paul. ex Fest. p. 235 Müll.
  2. II. Trop., of style, straightforwards, i. e. prosaic, in prose, opp. to verse (post-class.): prorsum est porro versum, id est ante versum. Hinc et prorsa oratio, quam non inflexit cantilena, Don. Ter. Eun. 2, 3, 14: et prorsa et vorsa facundia veneratus sum, in prose and verse, App. Flor. 4, p. 361, 36.
    In this sense predominant (but not found in Cic.) in the form prosa oratio, prose, = soluta oratio, Quint. 1, 5, 18; 11, 2, 39: prosa eloquentia, Vell. 1, 17, 3; Sen. ap. Gell. 12, 2, 6; Col. 11, 1, 1; Plin. 5, 29, 31, § 112.
    Subst.: prōsa, ae, f., prose, Quint. 1, 8, 2; 8, 6, 17; 20; 9, 4, 52 et saep.

1. prōsa ōrātĭo, and prōsa, v. 2. prorsus, II.

2. prōsa, ae, v. 2. prorsus, II.