| English | eng-000 |
| observing aperture | |
| 普通话 | cmn-000 | 观察孔 |
| English | eng-000 | eye split |
| English | eng-000 | glory-hole |
| English | eng-000 | observation door |
| English | eng-000 | observation hole |
| English | eng-000 | observation port |
| English | eng-000 | peep door |
| English | eng-000 | peep hole |
| English | eng-000 | prothole |
| English | eng-000 | sight |
| English | eng-000 | sight window |
| English | eng-000 | sightglass |
| English | eng-000 | sighting slit |
| English | eng-000 | viewing port |
| English | eng-000 | wicket |