nounDownload🔗ShareThe 14th letter of Classical and Modern Greek. The 15th in Ancient and Old Greek.Examples:"In my Greek alphabet practice, I always mix up xi (Ξ, ξ) with psi (Ψ, ψ) because they look similar. "languagewritingcharacterlinguisticsChat with AIVocabulary GamePractice Reading
nounDownload🔗ShareEither of a pair of hyperons having spin 1/2, which decay into a lambda particle and a pion.Examples:"After its creation in the high-energy collision, the xi quickly decayed into a lambda particle and a pion. "physicselementChat with AIVocabulary GamePractice Reading