Flickering light is a phenomenon that occurs when a light source rapidly turns on and off, creating a strobing or flashing effect. The term 'flickering light' can be used to describe both natural and artificial light sources. In the crossword puzzle, two words that can be used to describe this phenomenon are 'strobe' (6 letters) and 'FLARE' (5 letters). A strobe is a type of artificial light source that produces a very short, intense burst of light, while a FLARE is a bright light that is used to signal distress or attract attention.