The C89 Standard, also known as ANSI C, is a programming language standard established by the American National Standards Institute (ANSI) in 1989. It formalized the syntax and semantics of the C programming language, ensuring consistency across different compilers and platforms. This standardization helped developers write portable code that could run on various systems without modification. C89 introduced several key features, including function prototypes, improved type checking, and the standard library, which provides essential functions for tasks like input/output and string manipulation. By defining these elements, C89 laid the groundwork for future developments in the C language and influenced many other programming languages.