罗斯(luó sī) - Ross, Rose (transliterated name) in Mandarin

罗斯 (luó sī) is a transliteration, not a Chinese word with a meaning of its own. It renders the foreign syllables ross or rose, so it turns up as the name Ross, as a surname, and inside longer borrowed names.

You will meet the same two characters embedded in country and place names, most often 俄罗斯 (é luó sī, Russia) and 白俄罗斯 (Belarus). Those are single units: 罗斯 inside them is not a word you can pull out and use on its own.

The point for a learner is the principle rather than this particular name. When you see a run of characters that makes no sense semantically, check whether it is a transliteration. 罗 and 斯 are two of the workhorse characters for that job, along with 尔, 特, 克 and 拉, and spotting them saves you hunting for a meaning that was never there.