A code can be a set of principles. Our laws make up our legal code, and many people govern themselves through a personal "code of honor." Code can also mean a system for sending secret messages, or programming language for computers.

In 1303, you could only use code to mean a set of laws, such as a code of conduct. It wasn’t until 1808 that you could use code to describe a system for sending secret messages. The verb form appeared in 1815, meaning to create laws or send secret messages, and gave birth to encode. In the computer programming context, encode was shortened back again to code, meaning to write instructions for a computer program. Soon the lines of text themselves began to be referred to as simply code.

Definitions of code
  1. noun
    a set of rules or principles or laws (especially written ones)
    synonyms: codification
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    traditional code of the Japanese samurai which stressed courage and loyalty and self-discipline and simple living
    legal code
    a code of laws adopted by a state or nation
    building code
    set of standards established and enforced by local government for the structural safety of buildings
    dress code
    a set of rules specifying the correct manner of dress while on the premises of the institution (or specifying what manner of dress is prohibited)
    fire code
    set of standards established and enforced by government for fire prevention and safety in case of fire as in fire escapes etc
    a code of silence practiced by the Mafia; a refusal to give evidence to the police about criminal activities
    health code, sanitary code
    set of standards established and enforced by government for health requirements as in plumbing etc
    Highway Code
    the code of rules governing the use of public roads
    Justinian code, Roman law, civil law, jus civile
    the legal code of ancient Rome; codified under Justinian; the basis for many modern systems of civil law
    Salic law
    the code of laws of the Salian Franks and other German tribes
    criminal law
    the body of law dealing with crimes and their punishment
    penal code
    the legal code governing crimes and their punishment
    U. S. Code, United States Code
    a consolidation and codification by subject matter of the general and permanent laws of the United States; is prepared and published by a unit of the United States House of Representatives
    type of:
    black and white, written communication, written language
    communication by means of written symbols (either printed or handwritten)
  2. noun
    a coding system used for transmitting messages requiring brevity or secrecy
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    access, access code
    a code (a series of characters or digits) that must be entered in some way (typed or dialed or spoken) to get the use of something (a telephone line or a computer or a local area network etc.)
    area code
    a number usually of 3 digits assigned to a telephone area as in the United States and Canada
    Universal Product Code, bar code
    code consisting of a series of vertical bars of variable width that are scanned by a laser; printed on consumer product packages to identify the item for a computer that provides the price and registers inventory information
    color code
    system using colors to designate classifications
    cipher, cryptograph, cypher, secret code
    a secret method of writing
    Morse, Morse code, international Morse code
    a telegraph code in which letters and numbers are represented by strings of dots and dashes (short and long signals)
    ZIP, ZIP code, postal code, postcode
    a code of letters and digits added to a postal address to aid in the sorting of mail
    back door, backdoor
    an undocumented way to get access to a computer system or the data it contains
    type of:
    coding system
    a system of signals used to represent letters or numbers in transmitting messages
  3. verb
    convert ordinary language into code
    synonyms: cipher, cypher, encipher, encrypt, inscribe, write in code
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    type of:
    convert information into code
  4. verb
    attach a code to
    Code the pieces with numbers so that you can identify them later”
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    type of:
    label, mark, tag
    attach a tag or label to
  5. noun
    (computer science) the symbolic arrangement of data or instructions in a computer program or the set of such instructions
    synonyms: computer code
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    address, computer address, reference
    (computer science) the code that identifies where a piece of information is stored
    ASCII, American Standard Code for Information Interchange
    (computer science) a code for information exchange between computers made by different companies; a string of 7 binary digits represents each character; used in most microcomputers
    binary code
    code using a string of 8 binary digits to represent characters
    ECC, error correction code
    (telecommunication) a coding system that incorporates extra parity bits in order to detect errors
    firmware, microcode
    (computer science) coded instructions that are stored permanently in read-only memory
    machine code, machine language
    a set of instructions coded so that the computer can use it directly without further translation
    object code
    the machine-language output of a compiler that is ready for execution on a particular computer
    operation code, order code
    the portion of a set of operation descriptions that specifies the operation to be performed; the set of operations in a computer
    computer software, package, software, software package, software program, software system
    (computer science) written programs or procedures or rules and associated documentation pertaining to the operation of a computer system and that are stored in read/write memory
    command, instruction, program line, statement
    (computer science) a line of code written as part of a computer program
    argument, parameter
    (computer science) a reference or value that is passed to a function, procedure, subroutine, command, or program
    cyclic redundancy check
    an error correction code that is recorded in each sector of a magnetic disk and used to catch errors in the data
    URL, uniform resource locator, universal resource locator
    the address of a web page on the world wide web
    alpha software
    a first release of a software product that is usually tested only by the developers
    authoring language
    software that can be used to develop interactive computer programs without the technically demanding task of computer programming
    beta software
    software that has not yet been released but has received an alpha test and still has more bugs than a regular release
    compatible software
    software that can run on different computers without modification
    compatible software
    application software programs that share common conventions so they can be utilized together
    CAD, computer-aided design
    software used in art and architecture and engineering and manufacturing to assist in precision drawing
    software that is provided without charge
    software that can be used by a group of people who are working on the same information but may be distributed in space
    OS, operating system
    (computer science) software that controls the execution of computer programs and may provide various services
    computer program, computer programme, program, programme
    (computer science) a sequence of instructions that a computer can interpret and execute
    function, procedure, routine, subprogram, subroutine
    a set sequence of steps, part of larger computer program
    an instruction that interrupts the program being executed
    command line
    commands that a user types in order to run an application
    (computing) an instruction that connects one part of a program or an element on a list to another program or list
    macro, macro instruction
    a single computer instruction that results in a series of instructions in machine language
    system error
    an instruction that is either not recognized by an operating system or is in violation of the procedural rules
    any instruction that works first one way and then the other; it turns something on the first time it is used and then turns it off the next time
    software that is available free of charge; may be distributed for evaluation with a fee requested for additional features or a manual etc.
    shrink-wrapped software
    software on CD-ROMs that are boxed and shrink-wrapped and sold in stores (implying a widely supported standard platform)
    computer software that obtains information from a user's computer without the user's knowledge or consent
    supervisory software
    specialized programs that reside permanently in the computer's main memory and control the processing of user's programs
    documentation, software documentation
    program listings or technical manuals describing the operation and use of programs
    DBMS, database management system
    a software system that facilitates the creation and maintenance and use of an electronic database
    software that provides better performance than an earlier version did
    type of:
    coding system
    a system of signals used to represent letters or numbers in transmitting messages
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