bulla (noun F) : root vhal-; Gr. φαλ-; cf. φαλλός, φύλλον
* Any object swelling up, and thus becoming round; hence
* 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
* Trop., a bubble, trifle; vanity: si est homo bulla, eo magis senex,Varr. R. R. 1, 1, 1; Petr. 42, 4.
* Any thing rounded by art.
* 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).
* 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.
* The head of a pin in the water-clock, Vitr. 9, 6, 9 sq.

s. TLL