The Chinese word "格雷" is formed through phonetic transliteration, where the characters "格" (gé) and "雷" (léi) are chosen solely for their sounds to mimic the pronunciation of a foreign word, such as the English "Gary" or "Grey". This process involves selecting existing Chinese characters that, when combined, approximate the auditory impression of the original term, effectively borrowing it into Chinese without conveying the literal meanings of the individual characters.