1.
observation visit; attending to observe
Visiting a place to observe activities, most commonly used for parents visiting their child's school to observe classes. Also used for visiting factories, facilities, or events as an observer.
Usage
The most common usage is 授業参観 (classroom observation), where parents visit school to watch their children's classes. This is a regular event at Japanese schools. 参観日 (observation day) is the specific day set aside for this.