Is “Umbos” a Scrabble word?
Yes
UMBOS
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 Umbos
noun
1.A boss, or rounded elevation, or a corresponding depression, in a palate, disk, or membrane. For example the umbo in the integument of the larvæ of echinoderms or in the tympanic membrane of the ear.
2.One of the lateral prominences just above the hinge of a bivalve shell.
3.A bump or protrusion on the top of the cap.