The Chinese word 口哨 (kǒushào), meaning "whistle" (both the sound and the act of whistling), is a straightforward compound noun formed through semantic combination. It literally fuses 口 (kǒu), meaning "mouth", with 哨 (shào), which means "whistle", "to blow a whistle", or "sentry post". Thus, the term transparently denotes "a mouth-whistle" or "the act of whistling with the mouth", where the first character specifies the instrument (the mouth) and the second specifies the action or sound produced. This formation exemplifies a common pattern in Chinese where two meaningful characters (morphemes) are combined to create a precise, literal, and easily understood concept.