Question Summary:
What is meant by a wet dream?

Question Detail:

AsalaamuAlaykum. 
I need some clarification in regards to one masla. I have read many fatwa's on your site which state that if a person is sleeping and has a dream then upon waking up finds madhi on his clothing then ghusal is fardh. And on the other side if he does not have a dream and finds madhi when waking  up on his clothing then ghusal is not fardh.
My question is what is meant by having a dream. does it mean any random dream. Or does it mean seeing a women in a dream. Or does it mean seeing yourself having intercourse in the dream.
JAZAKALLAHU KHAIRAN

Answer :

In the Name of Allah, the Most Gracious, the Most Merciful.
As-salāmu ‘alaykum wa-rahmatullāhi wa-barakātuh.
Dream in the context refers to a sensational dream which the person believes led to the ejaculation. It does not refer to just any dream. It is also not necessary to see a woman or oneself having intercourse. 
And Allah Ta’āla Knows Best
Huzaifah Deedat
Student Darul Iftaa
Lusaka, Zambia
Checked and Approved by,
Mufti Ebrahim Desai.
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الاختيار لتعليل المختار-مطبعة الحلبي (1/ 12)
وَمَنِ اسْتَيْقَظَ فَوَجَدَ فِي ثِيَابِهِ مَنِيًّا أَوْ مَذْيًا  فَعَلَيْهِ الْغُسْلُ،
الدر المختار شرح تنوير الأبصار وجامع البحار (ص: 28)- دار الكتب العلمية
رؤية مستيقظ خرج رؤية السكران والمغمى عليه المذي، منيا أو مذيا (وإن لم يتذكر الاحتلام) إلا إذا علم أنه مذي أو شك أو ودي أو كان ذكره منتشرا قبيل النوم