a system of letters, numbers, words, or symbols used to represent and replace those conveying the meaning of a text, e.g. to keep it secret or to communicate it briefly
a system of numbers, symbols, etc that conveys information or instructions to a computer
a particular set of letters, numbers, etc identifying or representing a particular object
= area code
= genetic code
a systematic body of laws, esp one established by statutes
a set of rules or principles governing the behaviour of a particular group or individual