Is “Thornback” a Scrabble word?
Yes
THORNBACK
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 Thornback
noun
1.Any animal with a thorny back, especially marine animals, such as:
2.A woman over a certain age (variously 26 or 30) who has never married, older than a spinster.