聴講

ちょうこう · choukou · JLPT N1 · noun

attendance

🎓 聴 listen + 講 lecture = listening to a lecture, often sitting in without enrolling for credit

聴 (chou) is listen and 講 (kou) is lecture, so 聴講 is hearing a lecture. Auditing a course means attending it without taking it for credit.