Is “Theta” a Scrabble word?
Yes
THETA
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 Theta
/ˈθiːtə/
noun
1.The eighth letter of the Modern Greek alphabet, ninth in Old Greek: Θ, θ.
2.The measure of an angle.
3.The sensitivity of the value of a derivative with respect to time; the "time decay".