| 1 | Old French | bulle | seal; a letter sealed with a bull |
| 2 | Medieval Latin | bulla | seal; sealed document; seal capsule; seal",... |
| 3 | Latin | bulla | a bubble; a swollen or bubble-shaped object,... |
| 4 | Proto-Indo-European | bʰel- | to sound; to speak, roar, bark; shiny, white; to... |
| 5 | Proto-Indo-European | bʰōl- | — |