Is “Ostraca” a Scrabble word?
Yes
OSTRACA
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 Ostraca
noun
1.A piece of pottery or stone, usually broken off from a vase or other earthenware vessel, especially one used to cast a vote during the Ancient Greek process of ostracism.