1. When referring to a keyboard or symbol, the plus ( + ) is a symbol found on the same key as the equal sign. The plus key is most often used in programming and mathematics to add two or more numbers or as a programming operator. In a URL the + is used to represent a space, since spaces are not allowed in URLs.

2. Plus is also an abbreviated version of Google+.

3. Short for Microsoft Plus!

Also see: Hyphen, Keyboard terms