The character "口" was like human's mouth in the oracle bone inscription. Its original meaning was man's mouth. The meaning of "mouth" in modern Chinese is indicated by the character "嘴", but in ancient Chinese, it was indicated by the character "口". In modern Chinese, the basic meaning of "口" is still "mouth". However, it is no longer used alone, but only as a morpheme in the words such as "口腔" (oral cavity) and "口齿不清" (inarticulacy), etc. Later, it was extended to refer to opening of containers or entrance.