XP

Multiple definitions:

• Extreme programming.
• Experience Points in a role-playing game or in Everything2
• [AMD AthlonXP]? CPU
• as the Chi Rho, the symbol that the emperor Constantine I saw in the sky before the [Battle of the Milvian Bridge]? in 312. First two letters in Christ, therefore symbolic of Christianity.
• Short for the Windows XP operating system. One explanation for this name derives it from "experience"; another notes that "Cairo" was Microsoft's codename for elimination of MS-DOS code from Microsoft Windows; Windows XP (chi-rho) completes the process.