She confirmed to Billboard magazine that the album’s title is “4,” explaining:
“We all have special numbers in our lives, and 4 is that for me. It’s the day I was born [September 4]. My mother’s birthday [January 4] and a lot of my friends’ birthdays are on the fourth. April 4 is my wedding date.”
Though she, not surprisingly, didn’t mention it, her husband Jay-Z’s birthday is December 4 and they both have the roman numeral tattooed on their ring finger.