The term 'water sound' can be broken down into four crossword solutions: PLASH (5 letters), SPLASH (6 letters), PLOP (4 letters), and RIPPLE (6 letters). PLASH is a sound made when something small falls into water, such as a pebble or a drop of rain. SPLASH is a louder sound made when something bigger falls into water, like a rock or a large SPLASH of liquid. PLOP is a sound made when something heavy falls into water, like a boulder or a heavy object. RIPPLE is a sound made when something disturbs the surface of the water, like a boat or a person swimming.