The word ‘Hindu’ used in ancient time and several cases can be mentioned as below :
The Hamdan, Persepolis and Naqsh-I-Rustam inscriptions of Persian monarch Darius mention a people ‘Hidu’ as included into his empire. These inscriptions are dated between 520-485 B.C.
It is even claimed that Asokan inscription (3rd-century B.C.), repeatedly use expressions like ‘Hida’ for ‘India’ and ‘Hida loka’ for ‘Indian nation’ (Junagadh, separate rock edict II).
In Persepolis Pahlavi inscription of Shahpur II (310 A.D.), the King has the title, “Shakanshah Hind Shakastan u Tuxaristan Dabiran Dabir”, i.e.; “King of Shakastan, minister of ministers of Hind Shakastan and Tukharistan”.
In the Avesta (dated between 5,000-1,000 B.c.), Hapta Hindu is used for Sanskrit “Sapta Sindhu”.
The term ‘Indoi’ was used in Greek literature by Hekataeus (late 6th-century B.c.) and Herodotus (early 5th century B.C.).
The Hebrew Bible uses ‘Hodu’ for India, which is a Judaic form of ‘Hindu’. The Hebrew Bible (Old Testament) is dated earlier than 300 B.C. Even today Hebrew spoken in Israel uses Hodu for India.
The Chinese used the term ‘Hien-tu’ for ‘Hindu’ at about 00 B.C. while describing the movement of Sai-Wang. Later Chinese travelers Fa-Hien (5th century A.D.) and Huen-Tsang (7th century A.D.) used a slightly modified term ‘Yint’ but the affinity to the term ‘Hindu’ was still retained.
Sair-ul-Okull (available in Turkish Library Makhtab-eSultania in Istambul), an anthology of pre-Islamic Arabic poetry contains a poetry written by Omar-bin-e-Hassham praising Mahdeva and referring to India as ‘Hind’ and Indians as ‘Hindu’.
Another poem in the same anthology by Labi-bin-eAkhtab-bin-e- Turfa dated around 1700 RC. also refers to India as ‘Hind’ and Indians as ‘Hindu’ mentioning four Vedas. The poem is also inscribed on columns of Lakshamin Narayan Mandir (also known as Birla Mandir) in New Delhi.
Sanskrit works like Meru Tantra and Brihaspati Agam (4th to 6th century A.D.) mentions the term ‘Hindu’
Pahoja, MH; Antiquity and Origin of the tenn ‘Hindu’; The Hindu Renaissance; Vo. 5, No.2; April 2007; Pp 18-19