Muamalat (also muʿāmalāt, , literally "transactions" or "dealings") is a part of Islamic jurisprudence, or fiqh. Sources agree that muamalat includes Islamic "rulings governing commercial transactions" and Majallah al-Ahkam al-Adliyyah).
However, other sources (Oxford Islamic Studies Online, Brian Kettell, and Wahbah al-Zuhayli’) give it a broader definition including civil acts and in general all aspects of fiqh that are not Ibadat (acts of ritual worship such as prayer or fasting). (See organizational chart of the structure of Islam below in "Principles" section.)
Mu'amalat provides much of the basis for Islamic economics, and the instruments of Islamic financing, and deals not only with Islamic legality but also social and economic repercussions and the rationale of its prohibitions (according to Monzer Kahf). Even a broad definition of Muamalat does not deal with all aspects of property and money in Islam, as zakat — compulsory alms giving that is one of the five pillars of Islam — is part of Ibadat division of fiqh.
commercial and civil acts or dealings under Islamic law, (Oxford Islamic Studies Online);
what involves acts of interaction and exchange of sureties and sales (Oxford Dictionary of Islam);
“the knowledge of Shariah rulings that relates to the practical aspects of a mukallaf (an accountable Muslim, i.e. an adult and mentally competent) in the area of business and financial dealings and derived from its detailed evidences.” (Abdullaah Jalil, Asharaf Mohd Ramli, Syahidawati Shahwan. Based on the definition of fiqh established by the founder of the Shafi'i school of fiqh, Al-Shafi‘i (204 AH))
all engagements that take place in business, ("corporate sharia elite" according to Patricia Sloane-White);
Islamic jurisprudence of transactions, and the principles upon which Islamic finance is based (M.R. Ab`Aziz); also the study of "the legal framework within which economic transactions are conducted in an Islamic society" and that "determines their contracts" (Monzer Kahf);
that aspect of Islamic jurisprudence that deals with civil obligations, (Jamal J.