| # | Name | Origin | Meaning | Gender | |
|---|---|---|---|---|---|
| 501 | Isrod | Norse | Brother of Isleif. | M | |
| 502 | Ivor | Norse | Lord. A variant of the name Ifor. Famous Bearer: Composer Ivor Novello (1893-1951). | M | |
| 503 | Jarnsaxa | Norse | A giant. | F | |
| 504 | Jolgeir | Norse | Brother of Radorm. | M | |
| 505 | Jord | Norse | Daughter of Night. | F | |
| 506 | Jormungand | Norse | The serpent who encircles the earth. | M | |
| 507 | Jorund | Norse | Son of Hrafn the Foolish. | M | |
| 508 | Jorunn | Norse | Chiefs love. | F | |
| 509 | Kalf | Norse | Half son of Asgeir. | M | |
| 510 | Kalman | Norse | A man from Ireland. | M | |
| 511 | Kare | Norse | Tremendous. | M | |
| 512 | Kari | Norse | Tremendous. | M | |
| 513 | Karli | Norse | Manly. | M | |
| 514 | Karr | Norse | From the marsh. | M | |
| 515 | Keki | Norse | From the ship's island. | F | |
| 516 | Kelda | Norse | Fountain or from the ship's island. | F | |
| 517 | Keldan | Norse | From the spring. | M | |
| 518 | Kell | Norse | From the spring. | M | |
| 519 | Kelsey | Norse | From the ship's island. | F | |
| 520 | Kelsey | Norse | From the ship's island. | M | |