To me an Arab is someone who speaks Arabic Language.. Even this is not totaly true,cause each of the 22 Nations calling theselves Arabs do not speak the same Arabic Language , for example if an Iraqi talk his own Arabic an Algerian never able to understand him and visa versa.
If you mean Arab National..this is too far from the true meaning of Nationality,cause No arab can move freely to another Arabic country!!..Even each Arabic country has its own Anthem, currency ,flag,satellite TV, Conistitution,closed borders to other Arabs & Locked Confined army.
If you compare Who is an Arab to who is an Indian,Chinese, American ,French or British.. you will realise that these last named are true Nations and An Indian,Chinese,American, French,and British are True Nationalities Where each country has a Unified character ,system and conistitution . And all citizens of these countries has their Nationality Registered in ALL DOCUMENTS of the Person.(i.e;Passport) .
But an Arab is never Registered as a nationality in any DOCUMENT that belong to any citizen of the 22 Nations calling theselves Arabs..
So we can summate who is an Arab... He is who barely speak Arabic..BUT NOT TRUE NATIONALITY.( donot tell me they share Islamic religion...cause many Nations are Muslims but not Arabs..and do not say same history..cause no single Nation of these 22 Nations share the same history with another)