Noun of place from the root غ ر ب (ḡ r b) of غَرْب (ḡarb, “west, occident”). Compare Hebrew מַעֲרָב (maʿărāḇ) and Aramaic ܡܥܪܒܐ (maʿrəḇā)
Practice speaking and memorizing "مغرب" and many other words and sentences in Arabic.