Ebbing and flowing is a term used to describe the cyclical nature of many natural phenomena, such as the tides. It is also used to refer to the rise and fall of emotions, ideas, and trends. The term is derived from the word 'EBB, ' which means to recede or diminish, and 'FLOW, ' which means to increase or swell. The crossword solution for this term is 'TIDAL, ' which refers to the regular rise and fall of the ocean's water level due to the gravitational pull of the moon and sun.