The term 'dusk-to-dawn period' refers to the time of day between dusk and dawn, when the sun is below the horizon and the sky is dark. This period is also known as NIGHT, which is a five-letter word that can be used to solve the crossword puzzle. During this period, the sky is usually illuminated by stars, the moon, and other sources of light. This period is often associated with peace and tranquility, as it is a time when most people are asleep and the world is quiet.