Is “Birthday” a Scrabble word?
Yes
BIRTHDAY
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 Birthday
/ˈbɜːθ.deɪ/
noun
1.The anniversary of the day on which someone is born.
2.The anniversary of the day on which something is created.
3.The date on which someone is born or something is created, more commonly called birthdate or date of birth.
verb
1.To celebrate one's birthday.