Bulla

1. n. A genus of marine shells. See Bubble shell.
2. n. A bleb; a vesicle, or an elevation of the cuticle, containing a transparent watery fluid.
3. n. The ovoid prominence below the opening of the ear in the skulls of many animals; as, the tympanic or auditory bulla.
4. n. A leaden seal for a document; esp. the round leaden seal attached to the papal bulls, which has on one side a representation of St. Peter and St. Paul, and on the other the name of the pope who uses it.

The word meanings were obtained from OPTED(The Online Plain Text English Dictionary), which is based on “The Project Gutenberg Etext of Webster’s Unabridged Dictionary” which is in turn based on the 1913 US Webster’s Unabridged Dictionary (See Project Gutenburg), as a text file.