Lewis & Short

1. sōlārĭum, ii, n. [sol].

  1. I. (Sc. horologium, which is expressed in Plin. 7, 60, 60, § 213.) A sundial: solarium dictum id, in quo horae in sole inspiciebantur, etc., Varr. L. L. 6, § 4 Müll.: ut illum Di perdant, primus qui horas repperit, Quique adeo primus statuit hic solarium, Plaut. Fragm. ap. Gell. 3, 3, 5; cf. Becker, Gallus, 2, p. 301 sq. (2d ed.): venter erat solarium, Aquil. ib. 3, 3, 4.
    1. B. Transf.
      1. 1. Ad solarium, a much-frequented place in the Forum where the sundial stood, Cic. Quint. 18, 59; Auct. Her. 4, 10, 14.
      2. 2. A clock in gen. (even a water-clock): cum solarium aut descriptum aut ex aquā contemplere, Cic. N. D. 2, 34, 87; cf. Censor. de Die Nat. 23 fin.
  2. II. A part of the house exposed to the sun, a flat house-top, a terrace, balcony, or the like, Plaut. Mil. 2, 3, 69; 2, 4, 25; Aug. ap. Macr. S. 2, 4; Suet. Ner. 16; id. Claud. 10; Pall. Mai, 11, 1; Vulg. 2 Reg. 16, 22; id. Jos. 2, 6; Dig. 8, 2, 17; Inscr. Orell. 3303; 4240; Isid. Orig. 15, 3 al.; cf. Becker, Gallus, 2, p. 200 sq. (2d ed.).
    Also on sepulchral monuments, Inscr. Orell. 4536.