Solar __, Blocking of the Sun by the Moon
Puzzle 7 of Countdown to 2020 Piece of Cake Pack
Question is: Solar __, Blocking of the Sun by the Moon
and the answer is: ECLIPSE
Word Meaning:
ECLIPSE — (astronomy) An alignment of astronomical objects whereby one object comes between the observer (or notional observer) and another object, thus obscuring the latter.
Definitions from Wiktionary.