What does ロス mean?
ロス is a Japanese noun meaning “loss; waste (e.g. of time)” in English. It is written as ロス in hiragana, and rosu in romaji. This word is part of JLPT N1 vocabulary.
Example sentence
近道を行って時間のロスを埋め合わせるつもりだ。
We are going to make up for lost time by taking a short cut.