koi

American  

[koi] / kɔɪ /

noun

1. any of various colorful cultivated forms of the common carp, Cyprinus carpio, apparently originating in Japan and other parts of eastern temperate Asia.

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koi British  

/ kɔɪ /

noun

1. any of various ornamental forms of the common carp

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Etymology

Origin of koi

1720–30; < Japanese, earlier kowi < kofi, Old Japanese kwofi < *kwopi carp

Explanation

Koi are a brightly colored version of carp, the large freshwater fish. The big orange-and-white striped fish swimming under the footbridge in a park or botanical garden are koi. Wild koi are found in lakes and rivers of East Asia, but most of these fish are domesticated, kept in ponds so people can admire their beautiful colors. The tradition of breeding koi to be bigger, fancier, and brighter started in 19th-century Japan. They can grow as long as three feet, and they come in dozens of colors. The Japanese koi, or "carp," is a homophone for a word meaning "love," and they've come to symbolize love and friendship.

Example Sentences

Mud had smothered a koi pond on the woman’s property, likely killing the fish, but two of four turtles were found alive.

From Los Angeles Times • Dec. 28, 2025

Dubbed “BB14,” this plump bruin and her three cubs have settled behind mansions, interrupted a Mahjong tournament, shut down streets, attracted a TV helicopter and snatched koi out of a man-made pond.

From The Wall Street Journal • Nov. 17, 2025

Four heat exchangers are submerged in the 1.7 metre deep water, which is also home to dozens of koi carp and tench – fish that have their own role in the operation.

From BBC • Nov. 15, 2025

The home features a “state-of-the-art gym and wellness area,” a home theater, a catering kitchen, a tennis court, a vegetable garden, a chicken coop, and a koi pond.

From MarketWatch • Oct. 14, 2025

I’m having a telepathic conversation with a giant koi, Percy said.

From "The Mark of Athena" by Rick Riordan