plus in WordNet English dictionary

1. 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"
   summation  addition  plus 
   
2. a useful or valuable quality
   asset  plus 
   

1. on the positive side or higher end of a scale
   "a plus value"; "temperature of plus 5 degrees"; "a grade of C plus"
   plus 
   
2. involving advantage or good
   "a plus (or positive) factor"
   plus  positive