The initials JK are used for a remarkably diverse range of people, places, and concepts across the globe. Most famously, it is the pen name of Harry Potter author J.K. Rowling and the nickname of BTS singer Jungkook, but it also includes actor J.K. Simmons and musician Jay Kay of Jamiroquai. Historically, the abbreviation strongly evokes Juscelino Kubitschek, the president of Brazil from 1956 to 1961, as well as philosopher Jiddu Krishnamurti and Gaelic Athletic Association founder J. K. Bracken. Beyond individuals, "JK" applies to the Indian union territory of Jammu and Kashmir (its ISO code), a Japanese slang term for high school girls (joshi kōsei) in compensated dating culture, and the specific Jeep Wrangler model produced from 2007 to 2018. It also represents businesses like the J. K. Organisation, an Indian conglomerate, and a Spanish airline, Spanair. This wide-ranging set of meanings—spanning literature, pop music, sports, politics, and technology—makes "JK" a uniquely versatile abbreviation.