According to Production Weekly, Wonder Woman will enter production under the name Nightingale.
Most big blockbusters use alternate titles to throw fans off when they're filming on location. It's been a long time since a Marvel Studios or Warner Bros. comic book movie was being filmed without one. Sometimes, they're relevant and sometimes seem arbitrary.
In the case of Nightingale, the obvious connection to draw is with Florence Nightingale, a nurse and philosopher whose name has come to be synonymous in popular culture with the phenomenon of a caregiver developing an emotional or romantic attachment to their patient.
In her early Golden Age appearances, Wonder Woman first met her love interest Steve Trevor when he crash landed in his jet. While nursing him back to health, the pair fell in love and she followed Trevor back to "Man's World" to become a champion of peace as Wonder Woman.
Wonder Woman is expected to begin principal photography soon for its planned June 23, 2017 relase date.