Lewis & Short

Jānĭcŭlum, i, n. [Janus],

  1. I. one of the hills of Rome, on which Janus was said to have built a citadel, Verg. A. 8, 358; Ov. F. 1, 245; cf. Liv. 1, 33; Mart. 4, 64, 3; Cic. Agr. 1, 5, 16; 2, 27, 74; id. Mil. 27, 74 al.
    Hence,
  2. II. Jānĭcŭlāris, e, adj., of Janiculum: mons, i. e. Janiculum, Serv. ad Verg. A. 6, 784.