The word 柜子 is formed by combining the meaningful core character 柜, which means "cabinet" or "cupboard", with the very common and often meaningless suffix 子. The suffix 子 is added primarily to create a two-syllable word, which fits the rhythmic pattern of modern Chinese, and to nominalize the concept, turning it into a standard, everyday term for the object. The first character provides the specific meaning, while the second character acts as a grammatical particle that completes the word's form.