plus

nouns

a useful or valuable quality
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"

adjectives

on the positive side or higher end of a scale
"a plus value"; "temperature of plus 5 degrees"; "a grade of C plus"
antonym
is similar to
either positive or zero
is similar to
greater than zero
"positive numbers"
involving advantage or good
"a plus (or positive) factor"