noun
admission ticket; gallery ticket
Specifically a ticket to observe a public proceeding such as a court trial, Diet session, or other official hearing.
裁判の傍聴券を手に入れるために朝早くから並んだ。
I lined up early in the morning to get a gallery ticket for the trial.
傍聴 is the act of observing or auditing a public proceeding; 傍聴券 is the physical ticket that grants admission.
Compound of 傍聴 (observing, auditing) and 券 (ticket).