Madeline comes from Magdalene — referring to Mary Magdalene, the New Testament figure from the town of Magdala on the Sea of Galilee. The Hebrew root migdal means "tower" or "high place."
Madeline is the French form (Madeleine) Anglicised. Ludwig Bemelmans' 1939 children's book Madeline about the Parisian schoolgirl with red hair has kept the name visible for generations.
Madeline reduces to five — the number of curiosity and quiet bravery.