An expression of affirmation that translates most closely to ‘My God, may it be so!’ in English. It is the Arabic equivalent of the term ‘Amen’ used commonly in Christianity.

Āmīn or its longer variant, ilāhi āmīn, may be said after the completion of a duʿā (supplication). It can also be used conversationally in order to agree with another’s statement. 

In the practice of Sunnī Islam, the term āmīn is included in ṣalāh (ritual prayer) after completing the first recitation of Sūrah al-Fātiḥah. However, Shīʿah Muslims do not practice this because it is understood to invalidate the prayer. There is no barrier to Muslims of both sects praying in congregation, however, those following Shīʿah jurisprudence will refrain from reciting āmīn in this way.