The term 'PERTAINING TO THE MOON' can be summarized by two crossword solutions: SELENIC (7 letters) and Lunar (5 letters). SELENIC is derived from the Greek goddess of the moon, Selene, and refers to anything related to the moon. Lunar, on the other hand, is an adjective that describes anything related to the moon, such as its phases or its gravitational pull. Both terms are used to describe anything related to the moon, such as its physical characteristics, its orbit, or its effects on Earth.