adjective
always used before a noun :having a value that is above zero :positive
used after a letter grade (such as A, B, or C) to show that the work is slightly better than the letter by itself would indicate
used after a number to indicate a range greater than that number
on the plus side
used to describe the more appealing or attractive part of something
noun
plural pluses
[count] informal :something that is useful or helpful
mathematics :plus sign
preposition
used to indicate that one number or amount is being added to another
and also :as well as
plus or minus
used to indicate that a value, number, or amount may be above or below a certain number
conjunction
informal :in addition :and