The word 圣地亚哥 is formed through phonetic borrowing, where each character is chosen primarily for its sound to approximate the pronunciation of the foreign name "Santiago". The characters 圣 (shèng), 地亚 (dì yà), and 哥 (gē) are strung together in sequence to mimic the syllables "San-tia-go", with no inherent meaning from the original name being directly translated, resulting in a established phonetic transcription for the city name.