also: バースディ · バースデイ
Standard loanword for 'birthday', used in casual and commercial contexts. Often appears in compounds like バースデーケーキ (birthday cake) or バースデープレゼント (birthday present).
Today is my birthday.
I sent a birthday card to my friend.
We all celebrated our friend's birthday together.
I threw a birthday party for my daughter.
Everyone sang the birthday song together.