I.any object swelling up, and thus becoming round; hence,
I. A waterbubble, bubble: “ut pluvio perlucida caelo Surgere bulla solet,” Ov. M. 10, 734: “crassior,” Mart. 8, 33, 18; Plin. 31, 2, 8, § 12; App. M. 4, p. 145, 7.—Hence,
B. Trop., a bubble, trifle; vanity: “si est homo bulla, eo magis senex,” Varr. R. R. 1, 1, 1; Petr. 42, 4.—
II. Any thing rounded by art.
A. A boss, knob (upon a door, etc.): “jussine in splendorem dari bullas has foribus nostris?” Plaut. As. 2, 4, 20: “bullas aureas ex valvis, auferre,” Cic. Verr. 2, 4, 56, § 124 (by such door-studs fortunate or unfortunate days were designated, Petr. 30, 4).—
B. A stud in a girdle: “notis fulserunt cingula bullis Pallantis pueri,” Verg. A. 12, 942; 9, 359; Aus. Cup. Cruc. 49; Prud. Psych. 476.—
C. The head of a pin in the water-clock, Vitr. 9, 6, 9 sq.—
III. Esp., the bulla, a kind of amulet worn upon the neck (mostly of gold), orig. an ornament of the Roman triumphers, in imitation of the Tuscan kings and Lucumones (Plut. Romul. 25; “Fest. s. v. sardi, p. 252), but in the more brilliant era of the Romans worn by noble youths,” Cic. Verr. 2, 1, 58, § 152 (cf. Ascon. in h. l., acc. to whom bullae of leather were hung upon the necks of the children of freedmen); “it was laid aside when they arrived at maturity, and consecrated to the Lares,” Pers. 5, 30; cf.: “Lares bullati,” Petr. 60, 8; acc. to Plin. 33, 1, 4, § 10, first hung by Tarquinius Priscus upon the neck of his son; cf. also Macr. S. 1, 6, 9 sqq.; Plaut. Rud. 4, 4, 127; Liv. 26, 36, 5; Prop. 4 (5), 1, 131; Suet. Caes. 84; Flor. 2, 6, 24.—From the Etruscan custom, called Etruscum aurum, Juv. 5, 163.—Hence the phrase bullā dignus for childish: “senior bullā dignissime,” Juv. 13, 33.—It was also hung upon the forehead of favorite animals, Ov. M. 10, 114.