Definitions of code:

• noun:   a coding system used for transmitting messages requiring brevity or secrecy
• noun:   (computer science) the symbolic arrangement of data or instructions in a computer program or the set of such instructions
• noun:   a set of rules or principles or laws (especially written ones)
• verb:   attach a code to

  Example: "Code the pieces with numbers so that you can identify them later"

• verb:   convert ordinary language into code

  Example: "We should encode the message for security reasons"

• name:  A surname (very rare: popularity rank in the U.S.: #38357)