Hibernia is the Classical Latin name for the island of Ireland. The name Hibernia was taken from Greek geographical accounts. During his exploration of northwest Europe (c. 320 BC), Pytheas of Massilia called the island Iérnē (written Ἰέρνη). In his book Geographia (c. 150 AD), Claudius Ptolemaeus ("Ptolemy") called the island Iouerníā (written Ἰουερνία). It is likely that the Romans saw a connection between these historical names and the Latin word hibernus meaning wintry. In any case, the Roman historian Tacitus, in his book Agricola (c. 98 AD), uses the name Hibernia. The Romans also sometimes used Scotia, "land of the Scoti", as a geographical term for Ireland in general, as well as just the part inhabited by those people.
Iouerníā was a Greek alteration of the Q-Celtic name *Īweriū from which eventually arose the Irish names Ériu and Éire. The original meaning of the name is thought to be "abundant land".
Read more about Hibernia: Post-Roman Usage, Hibernia in The Historical Record, Ireland and Its Neighbours, Evidence of Roman Influence