Prelims
The use of the term Prelim (short for preliminary examination) varies and is synonymous with qualifying exam, but it generally refers to an examination (usually one from a sequence) that qualifies a student to continue studies at a higher level, and/or allow the student to comprehend his/her studies and see how prepared they are for the looming examinations. It is almost a gauge on how knowledgeable you are within the chosen subject. These exams are also referred to as Quals at some institutions.
Read more about Prelims: United States Graduate Programs, Singapore, Scotland and Latin America