The term 'CAT'S SOUND' can be broken down into three crossword solutions: PURR (4 letters), MEW (3 letters), and MEOW (4 letters). Cats make these sounds to communicate with other cats and humans. Purring is a low, continuous sound that cats make when they are content or happy. Mewing is a high-pitched sound that cats make when they are seeking attention or trying to communicate. Meow is the most common sound cats make and is used to express a variety of emotions, from happiness to anger.