A vague word with an unclear meaning that usually includes people speaking arabic as a mother tongue AND considereing themselves arabs. The word has a strong political impact since it can be used by real arab countries to manipulate whole populations.
"Hey, are you arab ?"
"No, I am Somalian"
"So you're arab then"
"Djibuti, Eritrea, Sudan, Somalia, Mauritania, Morocco, Algeria, Iran, Turkey, Egypt are NOT arab countries"
"Oh, I thought they were..."
"Nope, sorry, go sell your "arab solidarity" to some other countries"
"Saudi Arabia is an arab country"