If you define a direction on a plane as either positive or negative, what would you call its positive/negativeness? Its orientation? I feel like there is a better word out there for this.
So like, if there is an arrow that starts at (0,0) and has a slope of 1, and there is another arrow that starts at (0,0) and has a slope of -1, would I say, the first arrow is the same as the second arrow but with opposite orientation?