The Traditional Chinese characters 陰 and 陽 for the words yīn and yáng are both classified as radical-phonetic characters, combining the semantically significant "mound; hill" radical 阝 or 阜 with the phonetic indicators yin 侌 and yang 昜. The first phonetic yīn 侌 "cloudy" ideographically combines jīn 今 "now; present" and yún 云 "cloud", denoting the "今 presence of 云 clouds".[7] The second phonetic yáng 昜 "bright" features 日 the "sun" component. This phonetic is expanded with the "sun" radical into yáng 暘 "rising sun; sunshine". The "mound; hill" radical 阝full forms semantically specify yīn 陰 "shady/dark side of a hill" and yáng 陽 "sunny/light side of a hill".
Chinese wuji 無極 "limitless; infinite" is a compound of wu 無 "without; no; not have; there is not; nothing, nothingness" and ji 極 "ridgepole; roof ridge; highest/utmost point; extreme; earth's pole; reach the end; attain; exhaust". In analogy with the figurative meanings of English pole, Chinese ji 極 "ridgepole" can mean "geographical pole; direction" (e.g., siji 四極 "four corners of the earth; world's end"), "magnetic pole" (Beiji 北極 "North Pole" or yinji 陰極 "negative pole; cathode"), or "celestial pole" (baji 八極 "farthest points of the universe; remotest place").