| Abbreviation | Definition |
|---|---|
| JAM | Jesse Adam McCartney, musician and singer |
| JAM | Jonathan Alexander Mills |
| JAO | Jacob Aall Ottesen |
| JAP | James A Peterson |
| JAP | John A Prestwich |
| JAR | Jason Andrew Relva |
| JAS | James Alfred Scotchford |
| JAW | John A. Warmink, clock maker |
| JAZ | John Augustine Zahm |
| JB | Jack Black |
| JB | Jack Bruske, musician |
| JB | Jai Brooks |
| JB | James Baldwin |
| JB | James Bond |
| JB | Jeb Bush |
| JB | Jens Beckmann |
| JB | Jessica Buchanan |
| JB | Jim Blair |
| JB | Jimmy Buffett |
| JB | John Belden |