Below are listed some of the Arabic, and government-ese, terms that most readers may not be familiar with:

ALLAHU AKBAR = "God is the greatest."  A phrase traditionally used by Islamic fighters when entering battle, in modern usage it is used by terrorists when they behead someone, blow someone or something up, of commit a suicide operation.  It can also be used just to show astonishment or shock over something witnessed.

ANSAR AL-KITAB = means "the supporters of the Holy Book (Qur'an).  It is the name the novel's Arab terrorist/Jihadi organization have chosen for their movement.

APES and PIGS = A condescending nomenclature that the Qur'an applies to non-believers, particularly Jews. 

DAJJAL = Original meaning of word was counterfeit, or fraud, but has come to mean primarily "the Anti-Christ," or a personage to appear in the latter deals who will claim to be Jesus Christ, but is not, though he will fool many.

KAFIR = means "unbeliever."  In the modern sense can include Christians and Jews.  

KUFFAR = is the plural of KAFIR.

TAKFIRI = Refers to a person, or group, who calls other Muslims kafir, or "unbeliever."  This is a practice used by the more extreme radical Islamic groups such as ISIS.

KHALIFAH = Original mean was "the one who follows."  Then came to mean "the one who follows Muhammad as the Religious and Political leader of the entire Muslim community.  The Ottoman Turks held that title from the late Middle Ages until the end of the First World War.

KHELAFAH = The Caliphate (i.e. the state ruled by the Khalifah).

GHOTRA = The traditional male headdress in Arabia.

AL-MASJID AL-HARAM = The inviolab le mosque in Mecca where the Ka'aba is.

MINARATAYN = Two minarets

RUB' AL-KHALI = The Empty Quarter meaning the large uninhabited desert of sand dunes in southern Saudi Arabia.

UMMI = Mommy

POTUS = President of the United States

TDY = Temporary Duty, i.e. when someone in the military, or working for a government agency, is sent to work on another assignment in a location different than the one permanently assigned to.  These "temporary" duties can be any where from a day to several months depending upon the agency and the nature of the assignment.