| Abbreviation | Definition |
|---|---|
| JJ | Judge Jack |
| JJ | Jumping Jack |
| JJ | Jumping Jeffrey |
| JJ | Jumping Jenna |
| JJ | Justice Junior |
| JJ | Justin James |
| JJ | Justin Jasper |
| JJB | Jesse James Benjamin |
| JJU | Johnny Jump-Up |
| JK | Janine Karen |
| JK | Jeyakanthan |
| JK | Jiddu Krishnamurti |
| JK | Joanne Kathleen |
| JK | Joris Karl |
| JL | Jack Lurie |
| JL | Jackie Lee |
| JL | Japanese Lover |
| JL | Jeremiah Lucas |
| JL | Jerry Lembas |
| JL | John Lawrence |