The term Yamnat was mentioned in Old South Arabian inscriptions on the title of one of the kings of the second Himyarite kingdom known as Shammar Yahrʽish II. The term was probably referring to the southwestern cosatline of the Arabian peninsula and the southern cosatline between Aden and Hadramout. One etymology derives Yemen from ymnt, meaning "South", and significantly plays on the notion of the land to the right (𐩺𐩣𐩬). Other sources claim that Yemen is related to yamn or yumn, meaning "felicity" or "blessed", as much of the country is fertile. The Romans called it Arabia Felix (happy Arabia), as opposed to Arabia Deserta (deserted Arabia).
Classical Latin and Greek writers used the name "India" to refer to South Arabia (ancient Yemen). The use of the term "India" arise from the fact that the Persians called the Abyssinians whom they came into contact in South Arabia by the name of the dark-skinned people who lived next to them, i.e., Indians.