The Chinese word 窍门 (qiàomén) is a compound noun formed by combining two characters, each contributing to its metaphorical meaning: 窍 originally refers to a "hole," "aperture," or, by extension, a "key point" or "essential opening" in something, while 门 means "door" or "gate." Together, they create the image of a "doorway to the key point" or an "aperture that serves as a gateway," which evolved figuratively to mean a clever "knack," "trick," or "key method" to solving a problem—essentially, the crucial access point or shortcut to understanding or accomplishing something efficiently.