Meaning of “plus” - Learner’s Dictionary

plus

noun [ C ] us uk /plʌs/
GOOD THING informal

B2 an advantage:

Well, the apartment has a garden so that's a plus.
SYMBOL also plus sign, uk us

the symbol +, used between two numbers to show that they are being added together

(Definition of “plus noun” from the Cambridge Learner’s Dictionary © Cambridge University Press)