Is “Tonus” a Scrabble word?
Yes
TONUS
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 Tonus
noun
1.Tonicity; tone
“muscular tonus”