The word 咖啡 is formed through phonetic borrowing, specifically a transliteration from the English word "coffee". The two characters, 咖 (kā) and 啡 (fēi), were selected purely for their combined sound, which approximates the foreign pronunciation, with no inherent semantic connection to the beverage itself in their original meanings. This is a common method in Chinese for adopting foreign nouns, where characters are used as phonetic building blocks to construct a new term.