Ad-Din

Ad-Din (الْدِّين ad-dīn, "(of) the religion/faith/creed") is a suffix component of some Arabic names in the construct case, meaning 'the religion/faith/creed', e.g. Saif ad-Din (سيف الدّين Sayf ad-Dīn, "Sword of the Faith"). Varieties are also used in non-Arabic names throughout the Muslim world, It is used as a family name-suffix by some royal Muslim families, including the imperial Seljuks, Walashmas, Mughals, and the noble Alvi Hyderabadi families.

The Arabic spelling in its standard transliteration is al-Din. Due to the phonological rules involving the "sun letter" (حرف الشّمسيّة hurfu ’sh-Shamsiyyah), the Arabic letter د (dāl) is an assimilated letter of the Arabic definite article ال (al). This leads to the variant phonetic transliteration ad-Din. The first noun of the compound must have the ending -u, which, according to the assimilation rules in Arabic (names in general are in the nominative case), assimilates the following a-, thus manifesting into ud-Din in Classical and Modern Standard Arabic. However, all modern Arabic vernaculars lack the noun endings. Thus, the vowel of the definite article in them is pronounced in full as either a or e (the latter mostly in Maghreb and Egypt). At the same time, the Arabic short vowel u is rendered as short o in Persian, thus od-din.

In practice, romanizations of Arabic names containing this element may vary greatly, including:
 * al-Din, ad-Din, -addin, -adin
 * el-Din, -eldin, -eddin
 * ud-Din, -uddin (particularly in English-speaking South and East Asia), -uddeen (particularly in English-speaking South and East Asia)

Examples of names including this element are:
 * -eddine (particularly in French-speaking areas)
 * -ettin (particularly in Turkish names)
 * -od-din (particularly in Persian names)
 * Uddin (particularity in South Asia)


 * Aladdin
 * Alimuddin
 * Amin ud-Din
 * Anwaruddin
 * Asad ud-Din
 * Awwal ud-Din
 * Azharuddin
 * Azim ud-Din
 * Badr al-Din
 * Baha' al-Din
 * Burhan al-Din
 * Fakhr al-Din
 * Fariduddin
 * Ghiyath al-Din
 * Hamid al-Din
 * Haqq ad-Din
 * Hasan al-Din
 * Hisham ud-Din
 * Husam ad-Din
 * Ikhtiyar al-Din
 * Imad al-Din
 * Ismat ad-Din
 * Izz al-Din
 * Jalal ad-Din
 * Jamal ad-Din
 * Kamal al-Din
 * Khair ad-Din
 * Majd ad-Din
 * Mansur ad-Din
 * Mohy al-Din
 * Mohyeddin
 * Moinuddin
 * Muhib ud-Din
 * Mu'iz ad-Din
 * Muslih ud-Din
 * Najm al-Din
 * Nasir al-Din
 * Nazimuddin
 * Nizam al-Din
 * Nur al-Din
 * Qamar ud-Din
 * Qutb ad-Din
 * Rashid al-Din
 * Riazuddin
 * Rukn al-Din
 * Sa'd al-Din
 * Sadr al-Din
 * Safi al-Din
 * Saif al-Din
 * Ṣalāḥ ad-Dīn
 * Shams al-Din
 * Sharaf al-Din
 * Shihab al-Din
 * Shujauddin
 * Sirajuddin
 * Taj al-Din
 * Taqi al-Din
 * Zahir al-Din
 * Zayn ad-Din (or Zinedine)
 * Ziauddin

Use of Uddin as surname
In modern times in English-speaking environments, the name Uddin has sometimes been used as if it was a separate surname. An example is:
 * Pola Uddin, Baroness Uddin (born 1959), British politician

Use of Eddine as surname

 * Ahmed Saad Eddine, Egyptian politician