| # | Name | Origin | Meaning | Gender | |
|---|---|---|---|---|---|
| 621 | Jornr | Greek | Farmer. | M | |
| 622 | Judas | Greek | Greek form of Judah. The apostle, Judas Iscariot, betrayed Jesus Christ for thirty pieces of silver. As a result, the name Judas is used as a synonym for 'traitor' and is not often used as a first name. | M | |
| 623 | Jules | Greek | Variant of Julius: Downy. Hairy. Derived from the clan name of Roman dictator Gaius Julius Caesar. | M | |
| 624 | Julian | Greek | Youthlul. | M | |
| 625 | Julius | Greek | Downy. Hairy. Derived from the clan name of Roman dictator Gaius Julius Caesar. | M | |
| 626 | Juliusr | Greek | Youthlul. | M | |
| 627 | Jurgisr | Greek | Farmer. | M | |
| 628 | Kadmus | Greek | From the east. | M | |
| 629 | Kaj | Greek | Earth. | M | |
| 630 | Karen | Greek | Variant of Katherine. Pure. | M | |
| 631 | Karessa | Greek | Very dear. | M | |
| 632 | Karsten | Greek | Anointed. | M | |
| 633 | Kasmy | Greek | Order. | M | |
| 634 | Katharyn | Greek | Variant of Katherine. Pure. | M | |
| 635 | Kathleen | Greek | Variant of Katherine. Pure. | M | |
| 636 | Kathryne | Greek | Variant of Katherine. Pure. | M | |
| 637 | Kay | Greek | Variant of Katherine. Pure. | M | |
| 638 | Keril | Greek | Lordly. | M | |
| 639 | Kester | Greek | Diminutive of Christopher: From the Greek word meaning 'carrier of Christ', Famous bearer: St Christopher, patron Saint of travellers, is believed to have carried the Christ-child across a river. | M | |
| 640 | Kestorr | Greek | Christ bearer. | M | |