Front

spin of an object around its axis

Back

rotation

Front

line on which an object rotates

Back

rotation axis

Front

path an object follows as it moves around another object

Back

orbit

Front

orbit of one object around another object

Back

revolution

Front

Earth's rotation axis tilted directly toward or away from the Sun

Back

solstice

Front

Earth's rotation axis tilted neither toward nor away from the Sun

Back

equinox

Front

lit part of the Moon or a planet seen from Earth

Back

phase

Front

Moon phases with more of the near side lit each night

Back

waxing phase

Front

Moon phases with less of the near side lit each night

Back

waning phase

Front

central, darker part of a shadow where light is totally blocked

Back

umbra