also: ホワイトデイ
noun
White Day (March 14)
A Japanese custom where men give return gifts, typically white chocolate or other presents, to women who gave them gifts on Valentine's Day.
ホワイトデーに彼女からもらったチョコのお返しをあげた。
On White Day, I gave her a return gift for the chocolate I received on Valentine's Day.
日本では、3月14日はホワイトデーとして知
In Japan, March 14th is known as White Day.