This is because definitions and concepts are usually the important basis and premise of the paper. If these foundations and premises are plagiarized, the credibility and academic nature of the whole paper will be affected.

Therefore, when writing a thesis, we should not only pay attention to whether our written expression is accurate and clear, but also pay attention to whether the cited documents and definitions are consistent with the original author. It is best to use the citation format to avoid unnecessary trouble.

Finally, it is suggested that students do a comprehensive duplicate check before writing the paper to ensure that there is no plagiarism and plagiarism in the whole paper. This is very important to ensure the academic and credibility of the paper.

I hope my answer is helpful to you!