the plural is Christmases
The plural spelling is Ellises.
The plural spelling of luxury is luxuries.
The plural form of Christmas is Christmases.
The correct spelling of the plural of cyclist is cyclists.
The plural of flight is flights.
The plural of society is societies.
The plural of kangaroo is kangaroos.
The plural of tornado is tornadoes.
The plural form for the noun Christmas is Christmases.
The spelling Spurius is a proper noun, a Latin given name, with the English plural Spuriuses.The spelling spurious is an adjective, and has no plural.
The word Christmas is singular; the plural form is Christmases.
That is the correct spelling of the plural noun "coverages" (usually insurance).