2.  A round object, like a globe. In space, a planet, moon or star. Origin: 1250–1300; < LL sphēra, L sphaera globe < Gk sphaîra ball; r. ME spere < OF spere < LL spēra, var. of sphēra

3.  The line around which a body, or planet, rotates Origin: 1540–50; < L axis an axletree, axle, axis.

4.  In space, an orbit that is not flat but an elongated circle. Origin: 1745–55; < F < L ellīpsis ellipsis; or by back formation from the pl. ellipsesellipsis

5.  The two times a year (December and June) when the Earth’s axis points most towards or away from the sun. Longest and shortest days. Origin: 1200–50; < ME < OF < L sōlstitium, equiv. to sōl sun + -stit-, comb. form of stat-, var. s. of sistere to make stand ( see stand) + -ium - ium; see -ice)stand- ium-ice

6.  The step in the journey around the Earth that the moon takes; can be seen in 8 phases with different amounts of light and dark Origin: 1805–15; (n.) back formation from phases

8.  In science, when the moon is growing brighter from right to left.  Wax “on” Origin: bef. 900; ME waxen, OE weaxan; c. G wachsen; akin to waistwaist —Synonyms 1. extend, grow, lengthen, enlarge, dilate.

9.  In science, when the surface of the moon is growing darker from right to left. Origin: bef. 900; ME wanen (v.), OE wanian to lessen; c. MD, MHG wanen, ON vana to cause to wane, destroy

10.  When the moon is in the phase where the side facing the Earth is completely dark, no illumination.

11.  The phase in the lunar cycle wherein the right half of the moon is illuminated Origin: 1250–1300; (n.) ME < AF; OF quartier < L quartārius, equiv. to quart ( us ) fourth + - ārius -ary; (v.) ME quarteren, deriv. of the n.fourth-ary

12.  The phase of the moon when the left half is illuminated, opposite sides from 1 st quarter

13.  When the moon blocks light from the Sun from landing on the Earth Origin: 1400–50; late ME < L sōlāris, equiv. to sōl sun + -āris -ar 1 sun-ar

15.  When the Earth gets in the way of the Sun’s light and casts a shadow on the moon Origin: 1585–95; < L lūnāris of the moon. See LunaLuna

17.  Dark spots on the surface of the moon  Caused by asteroids hitting the surface hard enough that lava seeped up and filled in the surface Origin: 1680–90; < L: sea

18.  Twice a year (March and September) when the Earth’s axis is halfway between the two extreme points, creating 12 hours of light and 12 hours of dark equinox late 14c., from O.Fr. equinoxe, from M.L. equinoxium "equality of night (and day)," from L. aequinoctium, from aequus "equal" + nox (gen. noctis ) "night." The O.E. translation was efnniht. Related: Equinoctial

19.  An object that moves or spins on its axis.

20.  One body going around another body  Moon revolves around Earth  Earth revolves around Sun revolution late 14c., originally of celestial bodies, from O.Fr. revolution, from L.L. revolutionem (nom. revolutio ) "a revolving," from L. revolutus, pp. of revolvere "turn, roll back"