Is “Polygon” a Scrabble word?
Yes
POLYGON
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 Polygon
/ˈpɒliɡɒn/
noun
1.A plane figure bounded by edges that are all straight lines.
2.The boundary of such a figure.
3.(more generally) A figure comprising vertices and (not necessarily straight) edges, alternatingly.