| Term | Definition | Contributor | Modified |
|---|---|---|---|
| Zélée (Ship) | No definition provided | Christopher Rauch | 2023.12.01 |
| Zellerite | No definition provided | Ryan McGranaghan | 2023.04.16 |
| Zemannite | No definition provided | Ryan McGranaghan | 2023.04.16 |
| Zemkorite | No definition provided | Ryan McGranaghan | 2023.04.16 |
| Zenana missions | No definition provided | Christopher Rauch | 2023.12.01 |
| Zend-Avesta | No definition provided | Christopher Rauch | 2023.12.01 |
| Zend language | No definition provided | Christopher Rauch | 2023.12.01 |
| zenith | No definition provided | Ryan McGranaghan | 2023.04.16 |
| Zenith | No definition provided | Ryan McGranaghan | 2023.04.16 |
| Zenith | The point on the celestial sphere directly above the observer's head, opposite to the direction in which gravity acts. Opposite of nadir. | Ryan McGranaghan | 2023.04.16 |
| Zenith Angle SZA | No definition provided | Ryan McGranaghan | 2023.04.16 |
| Zenith hourly rate | The number of meteors expected to be seen under ideal conditions if the radiant of the meteoroid stream is at the zenith of the observer. | Ryan McGranaghan | 2023.04.16 |
| Zenith telescope | No definition provided | Christopher Rauch | 2023.12.01 |
| Zenith telescopes | A telescope that is mounted on a vertical axis or moves only a small amount from the vertical. It is primarily used to determine positional measurement of stars moving near the zenith. The advantage i s that there is no atmospheric refraction occurring at the zenith. If a star on one night passes through the center of eyepiece, one must observe it six month later, and see if the star has been offset by the center. A shift would mean a measure of parallax. | Ryan McGranaghan | 2023.04.16 |
| Zenith tubes | No definition provided | Ryan McGranaghan | 2023.04.16 |
| Zenith tubes | No definition provided | Ryan McGranaghan | 2023.04.16 |
| Zenzenite | No definition provided | Ryan McGranaghan | 2023.04.16 |
| Zeolites | No definition provided | Christopher Rauch | 2023.12.01 |
| Zeophyllite | No definition provided | Ryan McGranaghan | 2023.04.16 |
| zephyr | Any soft, gentle breeze. | Ryan McGranaghan | 2023.04.16 |