The Chinese word 纽扣 (niǔkòu), meaning "button", is a compound noun formed through semantic combination, where both characters contribute related meanings to create a specific concept. The first character, 纽 (niǔ), originally refers to a knot, bond, or something that can be twisted or tied, capturing the idea of a fastened loop. The second character, 扣 (kòu), means to button up, fasten, or deduct, emphasizing the action of securing. Together, they merge the object (the button itself, 纽) with its primary function (the act of fastening, 扣), resulting in a precise term for a small fastener used on clothing. This formation is typical in Chinese, where two meaningful morphemes combine to define a concrete everyday item.