Differentiate the definition between exchange and drainage

   Most of the drawbacks that were taken on the science of exchange
 came as a result of the lack of distinction between the terms mentioned in this science by those interested in it.
     The first problem, in my view, is the naming of the science itself, and it has two names: exchange once, and conjugation another, without distinguishing between them, despite the efforts of some researchers to differentiate between them, and to reach a clear and accurate understanding of this issue.
     This research is a serious attempt to understand the reasons behind this confusion, and to reach an accurate definition of each of these two terms, and to prove that exchange is not discharges, indicating their respective boundaries precisely with scientific evidence and accurate historical follow-up, and by analyzing the texts related to them.
The research should be divided into three main points:

 First: The reasons for this confusion. Second, the two terms follow a history and a subject. Third: Establishing an inclusive blocking definition for each.