text: what does the term "garbage in, garbage out" mean?   it is a term adopted early in computer use and commonly abbreviated to gigo. (garbage in, garbage out). it refers to the programmer's first rule that computers don't make mistakes but in-putters do. thus if you input incorrect information the computer doesn't know that it is incorrect and processes it according to it's directive. if you put erroneous information in you'll get erroneous information coming out, thus 'garbage in - garbage out'. it's not a term you hear much anymore.