| Acronym | Definition |
|---|
| NK | No Kidding |
| NK | Natural Killer (immunology) |
| NK | neck |
| NK | North Korea |
| NK | Not Known |
| NK | Nogometni Klub (Croatian: Football Club) |
| NK | Ninja Kiwi (game developer; New Zealand) |
| NK | Nippon Kaiji Kyokai (ship classification society) |
| NK | Spirit Airlines |
| NK | North Kitsap |
| NK | Neurokinin |
| NK | Nordiska Kompaniet (Swedish department store) |
| NK | No Keyword |
| NK | Noritsu Koki (Japan) |
| NK | New York to Key West (routing designation; US Navy) |
| NK | Neuroenergetic Kinesiology |
| NK | Nippon Kasei (Nippon Kasei Chemical Co., Ltd. Japan) |
| NK | Naked Killer (Diablo 2/LoD game) |
| NK | Nice Kill (gaming) |
| NK | North Kanara (Indian district) |
| NK | Naya Kadam (Suriname) |
| NK | North Karana (Everquest) |
| NK | Nuclear Kill (warhead) |
| NK | Northern Plains of Karana (Everquest) |
| NK | Newton-Kantorovich Method |
| NK | Nice Kicker (online poker) |
| NK | Nanokiero Media (Internet company) |