ちょうこう聴講choukou
1.

The act of attending a lecture to listen and absorb the information presented without necessarily participating or receiving credit.

2.

The practice of engaging in educational lectures or talks primarily for the purpose of learning or gaining knowledge, often in an informal or observational role.

Example:

聴講切符を前もって入手しておかなければならない。

ちょうこうせい聴講生choukousei
1.

A person who attends lectures at a university or educational institution without being officially enrolled as a student, typically granted permission to listen and learn from the classes.

2.

An individual who participates in academic courses to gain knowledge without pursuing a formal degree or obtaining academic credit, often for personal or professional development.

3.

Someone who observes and engages in educational sessions at a higher learning institution while not possessing the rights or status of a registered student.