Transliteration of the French female name Cosette (originally from Hugo's 1862 novel 《
悲惨世界》 / Les Misérables). The standard published Chinese rendering is
珂赛特 Kēsàitè;
科塞蒂 is a subtitle-corpus variant where
蒂 (dì, 'stem of a flower') replaces
特 to feminize the ending.
科 (kē) carries the 'Co-' opening,
塞 (sài) the '-set-/sett-' middle.