plural xis
: the 14th letter of the Greek alphabet see Alphabet Table

Word History


Greek xei

First Known Use

15th century, in the meaning defined above

Time Traveler
The first known use of xi was in the 15th century

Dictionary Entries Near xi

Cite this Entry

“Xi.” Dictionary, Merriam-Webster, Accessed 10 Dec. 2023.

Kids Definition


: the 14th letter of the Greek alphabet
Ξ or ξ

Geographical Definition


geographical name

variants or Hsi or Si
river 300 miles (483 kilometers) long in Guangxi Zhuangzu and Guangdong, southeastern China, flowing east into the South China Sea
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