The word 洗澡 is formed by combining two characters: 洗, which means "to wash", and 澡, which in classical Chinese meant "bath" or "to bathe". While 澡 is rarely used alone in modern Chinese, its core meaning is retained here. Together, they create a compound with a verb-object conceptual relationship, literally "to wash a bath". This specific pairing has fused over time into a single, fixed unit meaning "to bathe" or "to take a shower", where the original literal sense of washing a bath has become an idiomatic whole.