In COBOL, CO stands for "Common Business Oriented Language". COBOL is a programming language that was designed specifically for business applications, such as finance, accounting, and payroll. COBOL was first developed in the late 1950s, and it quickly became popular in the business world because it was easy to use and understand, and it could handle large amounts of data. The "common" part of the acronym refers to the fact that COBOL was intended to be a language that could be used by a wide range of businesses, regardless of their specific industry or application. The "business-oriented" part of the acronym emphasizes the language's focus on business data and processing.