Miaphysitism (or henophysitism) is an idea about the nature of Christ. The idea says that Jesus Christ had two different aspects, one godly, and one human. It says these two aspects are united in one nature. They are indistinguishable, and they co-exist. This is very close to the idea of dualism which says that the mind and the body are separate things that combine to make one unit, the person. In the case of miaphysitism, the separate things are Jesus' divine and human traits.
Miaphysitism has often been considered by Chalcedonian Christians to be a form of monophysitism, but the Oriental Orthodox Churches themselves reject this characterization, Recently, the Eastern Orthodox and Roman Catholic Churches have begun to take this position more seriously.