The proper noun (holiday) Thanksgiving has a normal S plural, Thanksgivings.
The spelling is the same in any case, THANKSGIVING.
The plural way to spell studio is studios.
The plural is resources.
The plural is cantaloupes.
The plural is hooves.
The plural is cherries.
The plural is roses.
The plural is "emeralds."
The plural is bridges.
thanksgiving
The plural is "recesses".
The plural of "roar" is "roars".