Nighttime is the period of time between sunset and sunrise, when it is DARK outside. The 5-letter crossword solution for this term is 'NIGHT'. EVENING is the period of time between late afternoon and nightfall, and the 7-letter solution for this is 'EVENING'. DUSK is the time of day when the sun is just below the horizon and the sky is beginning to darken, and the 4-letter solution for this is 'DUSK'. NIGHTLY is an adjective meaning occurring or done every NIGHT, and the 7-letter solution for this is 'NIGHTLY'. SUNDOWN is the time of day when the sun sets, and the 7-letter solution for this is 'SUNDOWN'. NOCTURNAL is an adjective meaning active at NIGHT, and the 9-letter solution for this is 'NOCTURNAL'. DARK is the absence of light, and the 4-letter solution for this is 'DARK'. DARKNESS is the complete absence of light, and the 8-letter solution for this is 'DARKNESS'.