The name Sunday is a girl's name . Sunday and is often added to lists like Middle Names for Girls and discussed in our forums with posts like "Love, Like, Lose -- Outlandish/Guilty Pleasures edition!".
From the experts:
Sunday is among the most usable of the day names, with its sunny opening syllable, made famous when Nicole Kidman and Keith Urban chose it for their newborn daughter. Although it had been widely written that Kidman and Urban named their baby after art patron Sunday Reed, Kidman recently was quoted saying that was a myth, they just liked the name. There were 34 baby girls named Sunday last year, but perhaps more parents will be inspired by the Kidman-Urban choice.