In a university, ideas are important, and it is also important to give people appropriate credit for having ideas. Plagiarism means using the ideas of someone else without giving them proper credit. That someone else may be an author, critic, journalist, artist, composer, lecturer, tutor or another student.
Intentional plagiarism is a serious form of cheating.
Unintentional plagiarism can result if you don't understand and use the acceptable scholarly methods of acknowledgment. In either case, the University may impose penalties which can be very severe. Over many years, procedures have been developed for acknowledging ideas in all forms of expression. In published writings, for example, authors are expected to give references to articles and books on which they have relied, and to give written thanks to people who have helped them in preparing their work. There are several methods for giving credit in written work and the lecturers and tutors in the academic units in which you study should inform you about methods that are acceptable to them.