Is “Costume” a Scrabble word?
Yes
COSTUME
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 Costume
/ˈkɒs.tjuːm/
noun
1.A style of dress, including garments, accessories and hairstyle, especially as characteristic of a particular country, period or people.
“The dancer was wearing Highland costume.”
2.An outfit or a disguise worn as fancy dress etc.
“We wore gorilla costumes to the party.”
3.A set of clothes appropriate for a particular occasion or season.
“The bride wore a grey going-away costume.”
Synonyms: outfit
verb
1.To dress or adorn with a costume or appropriate garb.