Yawmuddin is the Arabic word for the Day Of Judgement. It is used in the religion of Islam which encourages the use of the Arabic language due to the original documentation of the Qur'an.
In Islamic scripture and consistent belief, Yawmuddin refers to the day that one is judged by Allah, after a period of waiting. The belief in Islam is that one's soul waits in one's grave until the Day Of Judgement, when Allah judges you, preceding Akhirah (life after death). This is the point when Allah will terminate all living things, and the existence of this world.
References
Yawmuddin Wikipedia(Text) CC BY-SA