The syllabus is a summary of the topic, which is to be covered during lecture, academic course, or a test. In law, the syllabus is the summary of legal basic presented for any adjudicated case in which a summary of points is involved. The syllabus provides you with specific information about what is to be covered, and it is drafted by the governing body, which can be your instructor, head of the department, etc.
The syllabus also creates awareness for the students to know what they will be taught in the course. A good syllabus should contain the grading policies, textbooks, important dates like tests and exams, expectations of teachers from students, rules in the classroom, and also contain important details of the instructor like the email, phone numbers. Syllabi is the plural form of the syllabus. It contains a collection of syllabus which applies to more than one course.
If you would check out the difference between syllabus and syllabi, you will see that syllabi are known to be the plural version of the syllabus. What exactly is a syllabus? This is known to be the summary of the whole course.
For example, a certain subject will be discussed for the whole semester. The students have to know what they should expect from other people so as much as possible, they would like to know the outline of the lessons that they will learn. Take note that a syllabus must contain all the important points so that people can study their lessons ahead of time. Students may be given syllabi of the different courses that they are taking.