Etymology

The form is first attested in the Koran and is of uncertain origin. While the Christian Arabic name يسوع ‎(Yasūʽ) can be considered a phonetically regular equivalent of Hebrew ישוע ‎(Yešūaʽ), which is and has been believed to be Jesus’ historic name, the Koranic عيسى ‎(ʽĪsā) seems to be a phonetic modification. Several theories have been brought forward to explain why the letter ayn was apparently shifted from the last to the first position. It has been noted that ayn was not pronounced in some dialects of Aramaic, including that likely spoken by Jesus himself (compare for this Hebrew ישו). Moreover, there are indications that an unetymological word-initial ayn may have occurred more often in Arabic loans from Aramaic. Another popular theory, however unacceptable for Muslims, is that Muḥammad confused Jesus with Esau, in Arabic عيسو ‎(ʽĪsaw)—possibly due to an anti-Christian nickname used by Arabian Jews. For more information, see Isa (name) on wikipedia.