So-called bioengineering is, indeed, of an interdiscriplinary nature. It covers very huge fields and concerns many various concepts and ideas. Bioengineering, in this sense, appears to include the fields, in terms of terminology, of bioscience, biotechnology, biomaterials, biomechanical behaviour, biomechanics, and so forth. On the other hand, it seems to be difficult to draw distinctions among these fields, as is often the case in such interdisciplinary science and technology. Then the question may arise what are bioengineering, biotechnology, biomaterials, biomechanical behaviour, biomechanics, etc.? Herein, from this point of view, an attempt will be made to consider the interaction among the concepts and the prevalent approaches in each separate field called biomaterials, biomechanical behaviour, and biomechanics. Also, some approaches and methodologies that remain unknown have been pointed out for future new development of the research in the mechanical behaviour of bio- and biomedical materials and in bioengineering.