In this study, we analyzed how scientific terms such as principle, law and theory are depicted in Chemistry textbooks used by students in Singapore. There are very few reports in the science or chemistry education literature that explicitly explore the term principle, although all three terms appear in a number of topics in the high school chemistry curricula. The textbooks' definitions for the three terms were compared with key canonical attributes constituting these general terms. Findings indicate that most of the textbooks did not provide generic definitions of the three terms, and a number of attributes were also not apparent in the specific definitions of the three terms (except for principle). The relationship between laws and theories in textbooks was explored for three exemplars, and this provided useful insights. It is suggested that textbook authors, supported by curriculum developers and teachers, devote more attention to highlighting the relationships and distinctions among the three scientific terms. This can help students cultivate a better understanding of these terms, thus potentially leading to improved overall understanding of the nature of science.