Other forms: pluses
A plus is an “advantage” or an “asset.” You might look silly walking around with flippers all day, but if you lived underwater, they would definitely be a plus.
In Latin, the route plus means “more.” The word plus in English can have many senses, all relating to this idea of more, addition, or positive. This noun sense of the word means “a positive quality.” In the same way a number above zero on a number line is positive, and can use a plus sign, a plus is "a positive asset," like a superhero’s ability to fly or a spy’s ability to speak several languages.