'Plus' definitions:

Definition of 'plus'

(from WordNet)
adjective
On the positive side or higher end of a scale; "a plus value"; "temperature of plus 5 degrees"; "a grade of C plus" [ant: minus]
adjective
Involving advantage or good; "a plus (or positive) factor" [syn: plus, positive]
noun
A useful or valuable quality [syn: asset, plus] [ant: liability]
noun
The arithmetic operation of summing; calculating the sum of two or more numbers; "the summation of four and three gives seven"; "four plus three equals seven" [syn: summation, addition, plus]

Definition of 'Plus'

From: GCIDE
  • Plus \Plus\, a. [L., more; akin to Gr. ?, ?, and E. full. See Full, a., and cf. Pi[`u], Pleonasm.] [1913 Webster]
  • 1. (Math.) More, required to be added; positive, as distinguished from negative; -- opposed to minus. [1913 Webster]
  • 2. Hence, in a literary sense, additional; real; actual. [1913 Webster]
  • Success goes invariably with a certain plus or positive power. --Emerson. [1913 Webster]
  • Plus sign (Math.), the sign (+) which denotes addition, or a positive quantity. [1913 Webster]