Unreinforced masonry: Is designed assuming that flexural tensile stresses are resisted by masonry, and that the presence of any reinforcement is neglected in design. Unreinforced masonry can therefore actually have reinforcement in it, for structural integrity or by prescription. That reinforcement, however, is neglected in design calculations. Design is carried out in the linear elastic range.
Reinforced masonry: Is designed assuming that flexural tensile stresses cannot be resisted by masonry, and are resisted by reinforcement only. Shear stresses can be resisted by masonry or by reinforcement, singly or in combination. Design can be carried out by allowable stress design, or by strength design. Using this definition, unreinforced masonry can actually have reinforcement (for integrity or to meet prescriptive requirements).