a.  1.  
1.  (Math.) More, required to be added; positive, as distinguished from negative;  opposed to  
2.  Hence, in a literary sense, additional; real; actual.

Noun  1.  plus  a useful or valuable quality Synonyms: asset 
2.  plus  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"  
Adj.  1.  plus  on the positive side or higher end of a scale; "a plus value"; "temperature of plus 5 degrees"; "a grade of C plus" Antonyms: minus  on the negative side or lower end of a scale; "minus 5 degrees"; "a grade of B minus" 
2.  plus  involving advantage or good; "a plus (or positive) factor" Synonyms: positive 
1.  PLUS  Late 60's. Machineoriented systems language used internally by Univac.  
2.  plus  + Common: ITUT: plus; add. Rare: cross; INTERCAL: intersection. 