The Chinese word 咖啡因 (kāfēiyīn), meaning "caffeine", is a direct phonetic loan translation formed by combining the pre-existing transliteration for coffee, 咖啡 (kāfēi), with the character 因 (yīn), which is commonly used to phonetically represent the chemical suffix "-ine" (as in 尼古丁 nígǔdīng for "nicotine"). Thus, the word is constructed by borrowing the sound of the English term "caffeine" while logically segmenting it into the recognizable root for "coffee" and a standard phonetic placeholder for alkaloids and related chemical compounds.