night-night

American  

[nahyt-nahyt, -nahyt, nahyt-nahyt] / ˈnaɪtˈnaɪt, -ˌnaɪt, ˈnaɪtˌnaɪt /

interjection

1. Informal. good night.

---

idioms

1. go night-night, to go to bed or to sleep.

night-night British  

1. an informal word for good night

---

Etymology

Origin of night-night

First recorded in 1895–1900

Example Sentences

By day, the twins were racing go-karts, and when the sun set, it was night-night time in the family’s 25-foot Thor Delano RV.

From The Wall Street Journal • Dec. 28, 2025

It takes about a year to get what Roth calls the “perfect clunk and tinkle” — the Goldilocks zone between rock rebellion and night-night calm.

From Washington Post • Mar. 30, 2017

Another started calling nursing go night-night, and only did it when her 2-year-old was going to bed.

From Slate • Jul. 18, 2016

And ever since I’ve started looking at the science, I’ve become only more convinced that the earlier you say night-night, the better.

From Slate • May 10, 2016

It amused him that Jonas kissed their sweaty little necks and called night-night affectionately as they toddled off with their mother.

From "Son" by Lois Lowry