NK

Nk (or NK) is a two-letter combination that appears as an abbreviation in several fields and as a letter cluster in some languages. Its meaning depends on context, and it has no single canonical definition.

In biology, NK refers to natural killer cells, a type of lymphocyte in the innate immune system that can attack virus-infected and malignant cells without prior exposure. They play a role in early defense and secrete cytotoxic molecules and cytokines.

In international discourse, NK is commonly used as an abbreviation for North Korea (the Democratic People’s Republic of Korea) in schedules, maps, and shorthand analysis.

In economics, NK stands for New Keynesian economics, a framework incorporating price stickiness and microfoundations to explain short-run nominal rigidities and policy effectiveness.

In writing systems, nk is a common consonant cluster representing the sound sequence /ŋk/ in English and other languages after a vowel, as in pink or think.