Is “Xi” a Scrabble word?
Yes
XI
Valid in at least one Scrabble dictionary
Valid in these dictionaries
SOWPODS / CSW
Scrabble UK & International
TWL / NWL
Scrabble North America
Large English Dictionary
General English word list
Meaning of Xi
/ksaɪ/
noun
1.The 14th letter of Classical and Modern Greek. The 15th in Ancient and Old Greek.
2.Either of a pair of hyperons having spin 1/2, which decay into a lambda particle and a pion.