Hispania (Latin: Hispānia, Spanish:; nearly identically pronounced in Spanish, Portuguese, Catalan, and Italian) was the Roman name for the Iberian Peninsula and its provinces. Under the Roman Republic, Hispania was divided into two provinces: Hispania Citerior and Hispania Ulterior. During the Principate, Hispania Ulterior was divided into two new provinces, Baetica and Lusitania, while Hispania Citerior was renamed Hispania Tarraconensis. Subsequently, the western part of Tarraconensis was split off, first as Hispania Nova, later renamed "Callaecia" (or Gallaecia, whence modern Galicia). From Diocletian's Tetrarchy (AD 293) onwards, the south of the remainder of Tarraconensis was again split off as Carthaginensis, and all of the mainland Hispanic provinces, along with the Balearic Islands and the North African province of Mauretania Tingitana, were later grouped into a civil diocese headed by a vicarius. The name Hispania was also used in the period of Visigothic rule.

The modern place names Spain and Hispaniola are both derived from Hispania.
What is Hispania
Hispania (Latin: Hispānia, Spanish:; nearly identically pronounced in Spanish, Portuguese, Catalan, and Italian) was the Roman name for the Iberian Peninsula and its provinces. Under the Roman Republic, Hispania was divided into two provinces: Hispania Citerior and Hispania Ulterior. During the Principate, Hispania Ulterior was divided into two new provinces, Baetica and Lusitania, while Hispania Citerior was renamed Hispania Tarraconensis. 

Subsequently, the western part of Tarraconensis was split off, first as Hispania Nova, later renamed "Callaecia" (or Gallaecia, whence modern Galicia). From Diocletian's Tetrarchy (AD 293) onwards, the south of the remainder of Tarraconensis was again split off as Carthaginensis, and all of the mainland Hispanic provinces, along with the Balearic Islands and the North African province of Mauretania Tingitana, were later grouped into a civil diocese headed by a vicarius. The name Hispania was also used in the period of Visigothic rule.

The modern place names Spain and Hispaniola are both derived from Hispania.