Phonetic transliteration of the surname 'Dukes' (English) or 'Dukas/Ducas' (French/Greek). Compare
公爵 (gōngjué) which is the title 'Duke'. As a surname,
杜克斯 is an English-language proper name — the Greek-origin variant
杜卡斯 (Dùkǎsī) is sometimes used for the Byzantine imperial family Doukas.