Selene is the ancient Greek goddess of the moon
Luna is the ancient Roman goddess of the moon.
"Selenic" is an adjective and a synonym for "lunar"
They both mean.....of, relating to, or like the moon.
Lunar is commonly used when referring to the moon; selenic is rare.
Selenic also means.....of, relating to, or containing the element "selenium".
The element was named after the moon when discovered in 1817 by the scientist Berzelius.