The Greek name is based on the ethnonym Libu (Ancient Greek: Λίβυες Líbyes, Latin: Libyes). The name Libya (in use since 1934 for the modern country formerly known as Tripolitania and Barca) was the Latin designation for the region of the Maghreb, from the Ancient Greek (Attic Greek: Λιβύη Libúē, Doric Greek: Λιβύᾱ Libúā). In Classical Greece, the term had a broader meaning, encompassing the continent that later (second century BC) became known as Africa, which, in antiquity, was assumed to constitute one third of the world's land mass, compared to Europe and Asia combined.
The Libu are attested since the Late Bronze Age as inhabiting the region (Egyptian R'bw, Punic: 𐤋𐤁𐤉 lby). The oldest known references to the Libu date to Ramesses II and his successor Merneptah, pharaohs of the Nineteenth Dynasty of Egypt, during the 13th century BC. LBW appears as an ethnic name on the Merneptah Stele.
Menelaus had travelled there on his way home from Troy; it was a land of wonderful richness, where the lambs have horns as soon as they are born, where ewes lamb three times a year and no shepherd ever goes short of milk, meat or cheese.
Homer names Libya, in Odyssey (IX.95; XXIII.311). Homer used the name in a geographic sense, while he called its inhabitants "Lotus-eaters". After Homer, Aeschylus, Pindar, and other ancient Greek writers use the name. Herodotus (1.46) used Λιβύη Libúē to indicate the African continent; the Líbues proper were the light-skinned North Africans, while those south of Egypt (and Elephantine on the Nile) were known to him as "Aethiopians"; this was also the understanding of later Greek geographers such Diodorus Siculus, Strabo, etc.
When the Greeks actually settled in the real Libya in the 630s, the old name taken from the Egyptians was applied by the Greeks of Cyrenaica, who may have coexisted with the Libu. Later, the name appeared in the Hebrew language, written in the Bible as Lehabim and Lubim, indicating the ethnic population and the geographic territory as well.
In the neo-Punic inscriptions, it was written as Lby for the masculine noun, and Lbt for the feminine noun of Libyan.
Latin absorbed the name from Greek and the Punic languages. The Romans would have known them before their colonization of North Africa because of the Libyan role in the Punic Wars against the Romans. The Romans used the name Líbues, but only when referring to Barca and the Libyan Desert of Egypt. The other Libyan territories were called "Africa".
Classical Arabic literature called Libya Lubya, indicating a speculative territory west of Egypt. Modern Arabic uses Libya. The Lwatae, the tribe of Ibn Battuta, as the Arabs called it, was a Berber tribe that mainly was situated in Cyrenaica. This tribe may have ranged from the Atlantic Ocean to modern Libya, however, and was referred to by Corippius as Laguatan; he linked them with the Maures. Ibn Khaldun's Muqaddimah states Luwa was an ancestor of this tribe. He writes that the Berbers add an "a" and "t" to the name for the plural forms. Subsequently, it became Lwat.
Conversely, the Arabs adopted the name as a singular form, adding an "h" for the plural form in Arabic. Ibn Khaldun disagrees with Ibn Hazam, who claimed, mostly on the basis of Berber sources, that the Lwatah, in addition to the Sadrata and the Mzata, were from the Qibts (Egyptians). According to Ibn Khaldun, this claim is incorrect because Ibn Hazam had not read the books of the Berber scholars.
Oric Bates, a historian, considers that the name Libu or LBW would be derived from the name Luwatah whilst the name Liwata is a derivation of the name Libu.