Dolfin (T) derives from Latin name Delphinus (from Delphi). The Ancient Greek city of Delphi possibly took its name from the word delphys (womb). This name was also Venetian.
Drudmund (I) derives from Proto–Germanic root þrūþ (strength) and OId Saxon mund and Old High German munt (protection, hand).
Duccio (T, I) was a very fashionable Tuscan name, which originated as a superdiminutive of Andreuccio and nicknames ending in -duccio (e.g., Bernarduccio, Leonarduccio, Armanduccio).
Dimitillia (T, I) is probably a form of the Latin name Domitillia, from Roman family name Domitius and Latin word domitus (having been tamed).
Dionora, Dianora (I) may be an elaborated form of Diana (Divine, heavenly). This is the name of a character in the fifth story of the tenth day of The Decameron.
Divitia (I) comes from a Latin word meaning “riches, wealth.”
Doratea (I) is a form of Dorothea (gift of God).