Plusses meaning : A positive quantity. An asset or useful addition. A plus sign: +. To add; to subject to addition. (often followed by 'up') To increase in magnitude. To improve. To provide critical feedback by giving suggestions for improvement rather than criticisms. (sales) To sell additional related items with an original purchase. To frame in a positive light; to provide a sympathetic interpretation. (social media) To give a mark of approval on Google+. To increase the potency of a remedy by diluting it in water and stirring. (optometry) To increase a correction.