Is “Polyhedra” a Scrabble word?
Yes
POLYHEDRA
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 Polyhedra
/pɒl.iˈhiː.dɹə/
noun
1.A solid figure with many flat faces and straight edges.
2.A polyscope, or multiplying glass.