This is the 729th most frequent Russian word.
плюс
"Plus" - "plus" or "advantage."
Here, 'плюс' is used to mean a positive point or credit awarded for something.
Я получил плюс за активное участие в уроке.
I received a plus for active participation in the lesson.
Here, 'плюс' is used to indicate a positive temperature above zero.
Плюс пять градусов - это гораздо теплее, чем было вчера.
Plus five degrees is much warmer than it was yesterday.
In this sentence, 'плюс' is used as a conjunction meaning 'in addition' or 'also'.