Too broad understanding of the term "stress", which Selye himself and his followers used in their popular science works, reduces its scientific value. Based on a brief analysis of examples of the ambiguity of the term "stress", it is proposed to restore its research significance. For that, the concept of "stress" should be used more strictly and unequivocally and it would not be allowed to use a "commonly broad" understanding the term in scientific papers. In the frame of earlier Selye's stress definition, it suggests a more detailed structuring of the term based on levels of studying of living objects, including genetic.