_:vb7162332 "When the Moon is in quadrature, it appears in the sky as a half-moon."@en . "5" . . _:vb7162331 . _:vb7162331 "(astronomy) A situation in which the directions of two celestial bodies (or a celestial body and the Sun) form a right angle from the perspective of the observer."@en . _:vb7162332 .