Lewis & Short

sēcrētārĭum, ii, n. [secretus], a remote, solitary, or secret place (post-class.).

  1. I. In gen.: ignes qui terrae secretariis continentur, App. de Mundo, p. 64, 39; id. Flor. p. 358, 28.
  2. II. In partic., a sittingplace (set apart).
      1. 1. Of judges, a council chamber, Cod. Th. 1, 7, 1; Cod. Just. 3, 24, 3; 9, 3, 16; Lact. Mort. Pers. 15.
      2. 2. Of ecclesiastics, a consistory, conclave, Sulp. Sev. S. Mart. 2, 1; Paul. Nol. Ep. 32, 16.