(1) In chemistry, a theory advanced by Berzelius that every compound, no matter how many elements enter into it, is composed of two parts, one electrically negative, the other positive; still applicable, with modification, to polar compounds, but inapplicable to nonpolar compounds. (2) In hematology, the concept that blood cells have two origins, i.e., lymphogenous and myelogenous. (3) The theory that the mind and body are two distinct systems, independent and different in nature. [L. dualis, relating to two, fr. duo, two]
