| A | B |
|---|
| terminator | line separating night from day |
| cusp | also known as the horns of the moon that point away from the sun |
| waxing | refers to the phases of the moon in which the visible portion is growing |
| waning | refers to the phases of the moon in which the visible portion is decreasing |
| new moon | phase in which zero percent of the lighted portion is visible from Earth |
| full moon | phase in which 100 percent of the lighted portion is visible from Earth |
| crescent | phase in which less than half of the lunar disc is visible from Earth |
| gibbous | phase in which more than half of the lunar disc is visible from Earth |
| first quarter | phase in which the right half of the lunar disc is visible from Earth |
| third quarter | phase in which the left half of the lunar disc is visible from Earth |
| moonshine | sunlight reflected by the moon onto the Earth |
| Earthshine | sunlight reflected by Earth's atmosphere that illuminates the dark portion of the moon facing Earth |
| limb | the edge of the lunar disc |
| mare | Latin for sea |
| synodic | means relative to the Sun |
| sidereal | means relative to the stars |
| zenith | point above the observer's head |
| five | number of degrees between the moon's plane of motion and the ecliptic |
| daVinci | first person to explain the phenomenon of earthshine |
| 27.3 days | length of the moon's sidereal period |
| 29.5 days | , length of the moon's synodic period |
| elongation | angular distance between the sun and moon |
| harvest moon | full moon closest to autumnal equinox |
| hunter's moon | full moon following the harvest moon |
| counter clockwise | direction of rotation of the earth and revolution of the moon |
| celestial meridian | line that goes from north to south through the zenith |
| ecliptic | apparent path of the sun through the sky |
