interest(Sood)which is a lender receives over and above the principal (Ras ul Maal) in any loan transaction. This is real and primary form of Riba. Since the verses of the Holy Quran has directly rendered this type of Riba as haram, it is also called "Riba Al Quran". Similarly, since only this type was considered as Riba in the dark ages, so it has earned the name of Riba Al Jahiliyyah as well.
The meaning of Riba has been clarified in the following verses of Holy Quran.
"" That is because they have said:" Sale is but like riba", while Allah has permitted sale, and prohibtted riba" (Surah Baqarah; 275).
Imam Abu Bakr Jassas Razi( Rehmatullah eleh) has outlined a comprehensive legal definition of Riba An.Nasiyah in the following words;
" That kind of loan where specific repayment period and an amount in excess of capital is predetermind."
The famous Sahabi Hazrat Fazala Bin Obaid( Razi Allah anho) has also defined Riba in similar words:
"Every loan that draws profit is one of the forms of Riba."