Lewis & Short

gĕrūsĭa, ae, f., = γερουσία,

  1. I. the place of meeting for a council of old men, senatehouse in a Grecian city (= senaculum), Varr. L. L. 5, 32, § 156.
  2. II. A public hospital or retreat in Sardes, for old men who had deserved well of their country, Vitr. 4, 8; Plin. 35, 14, 49, § 172; Plin. Ep. 10, 42.