viewer
/ˈvjuːə(r)/noun
1
- a person who looks at or inspects something察看者, 观看者, 参观者。
1.1
- a person watching television or a film（电视或电影）观众。
2
- a device for looking at film transparencies or similar photographic images（观看电影透明正片或类似摄影图片的）看片器。