Earth, Moon, and stars

Axis

An imaginary line that passes through Earth's center and North and South poles, about which Earth rotates.

Rotation

The spinning motion of a planet about its axis.

Revolution

The movement of an object around another object.

Orbit

The path of an object as it revolves around another object in space.

Latitude

The distance north or south from the equator, measured in degrees.

Solstice

The two days of the year on which the noon sun is directly overhead at either 23.5 degrees South or 23.5 degrees North.

Vernal equinox

The day of the year that marks the beginning of spring in the Northern Hemisphere.

Autumnal equinox

The day of the year that marks the beginning of fall in the Northern Hemisphere.

Eclipse

The partial or total blocking of one object by another.

Solar eclipse

The blocking of sunlight to Earth that occurs when the moon is between the sun and Earth.

Umbra

The darkest part of a shadow.

Penumbra

The part of a shadow surrounding the darkest part.

Lunar eclipse

The blocking of sunlight to the moon that occurs when Earth is directly between the sun and moon.

Tide 

The daily rise and fall of Earth's waters on shores.

Phase

The appearance of the illuminated portion of the Moon as seen by an observer, usually on Earth. One of the different shapes of the moon as seen from the earth.

New moon

The phase of the moon occurring when it passes between the earth and the sun and is invisible or visible only as a narrow crescent at sunset.

Full moon

The moon when it is visible as a fully illuminated disk.

First quarter moon

The phase of the moon which is most easily spotted by the casual observer. You see the moon in this phase in the south as the Sun sets.

Third quarter moon 

Three weeks after the new moon, we again can see half of the illuminated part. This is usually called third quarter, or last quarter moon.

Waning crescent

A crescent moon moving towards a new moon.

Waxing crescent

A crescent moon moving towards a full moon.

Waning gibbous

More than half, but less than fully illuminated, and moving towards a new moon.

Waxing gibbous

1. More than half, but less than fully illuminated, and moving towards a full moon.