sol-, soli-, solo- +

(Latin: sun)

solarization
Exposure to natural or artificial sunlight for therapeutic purposes, as in a solarium.
solarize (verb), solarizes; solarized; solarizing
To convert, or to adapt, a building or site to the use of solar energy: Jim has an apartment in a building that has been solarized to utilize the sun to store electricity for the use of all the tenants living there.
solarolatry
Worshiping the sun; sun worship.
soliform
Like the sun in form, appearance, or nature; resembling the sun.
sol-lunar
A reference to or caused by the sun and moon.
solstice
1. Either of the times when the sun is farthest from the equator, on or about June 21 or December 21.

The summer solstice falls in June in the northern hemisphere but in December in the southern hemisphere, and vice versa for the winter solstice.

The summer solstice is the longest day of the year and the winter solstice is the shortest.

2. Either of the two points on the ecliptic when the sun reaches its northernmost or southernmost point relative to the celestial equator.
solstitial
1. Happening at a solstice; especially, (with reference to the northern hemisphere), happening at the summer solstice, or midsummer.
2. Of or pertaining to a solstice.
3. Characteristic of the summer solstice.
turnsole, turnsol
1. A plant of the genus Heliotropium; heliotrope; so named because its flowers are supposed to turn toward the sun; such as, the sunflower.
2. A purple dye obtained from the turnsole plant.

Related "sun" word family: helio-.