BULLA • DICCIONARIO INGLES.COM • Definition of Bulla

... box containing an amulet, worn suspended from the neck by children of noble birth until they assumed the toga virilis, when it was hung up and dedicated to the household gods. The custom of wearing the bulla, which was regarded as a charm against sickness and the evil eye, was of Etruscan origin. After the Second Punic War all children of free birth were permitted to wear it; but those who did not belong to a noble or wealthy family were satisfied with a bulla of leather. ...

— Encyclopaedia Britannica, 11th Edition, Volume 4, Part 4 - "Bulgaria" to "Calgary" • Various

... The bulla was a small object, enclosed in historical times in a capsule, and suspended round the child's neck. It was popularly believed to have been originally an Etruscan custom,[120] and borrowed by the Romans, like so many other ornaments. It is, however, ...

— The Religious Experience of the Roman People - From the Earliest Times to the Age of Augustus • W. Warde Fowler