'Cùn kǒu' literally means 'inch opening' — 'cùn' (inch) refers to the traditional Chinese unit of measurement used to locate pulse positions on the radial artery, and 'kǒu' (opening/mouth) metaphorically denotes a key diagnostic 'gateway' or point where vital energy (qì) manifests. In Traditional Chinese Medicine (TCM), cùn kǒu specifically names the standard pulse-taking site on the radial artery just below the wrist crease, divided into three sections (cùn, guān, chǐ) corresponding to different zàng-fǔ organs.

This term appears almost exclusively in clinical TCM contexts — during diagnosis, acupuncture training, or herbal medicine consultations. It is never used colloquially or outside medical practice. Mastery of cùn kǒu assessment requires years of training, as practitioners interpret subtle variations in pulse quality (e.g., wiry, slippery, deep) to assess internal balance. While modern biomedicine does not recognize this anatomical designation, it remains foundational in TCM theory and daily practice across China and East Asia.