The word "马拉松" is formed through a direct phonetic borrowing from the English word "marathon". The three characters 马 (mǎ), 拉 (lā), and 松 (sōng) were selected not for their individual meanings (which are "horse", "pull", and "pine tree", respectively), but because their combined pronunciation closely approximates the sound of the English source word. It is a classic example of a transliteration, where the form of a foreign word is adapted into Chinese using characters that mimic its sounds.