certificate of completion; diploma
Specifically refers to a document certifying that a course, program, or training has been completed. Often used for non-degree programs, workshops, or specialized training, as opposed to a graduation diploma (卒業証書).
I received a certificate of completion at the end of the course.
Upon completing this training, a certificate of completion will be issued.
卒業証書 is a graduation diploma, typically from a school or university, while 修了証書 is a certificate of completion for a specific course or program, not necessarily a full degree.
Compound of 修了 (completion of a course) and 証書 (certificate). The term is straightforward and modern.