The term code indicates a “Duplication Rule” which allows the correlation of every entity within its area of observation with a corresponding entity within the system.
[…] linguistic usage has developed, which can be read in formulations such as "secret code" , "Morse Code", "genetic code" or in the communication-theoretical speech of coding, decoding, recoding.
described as a 'stasis' between constructive and eliminative reduction. See JOHANSSON, Christer, 1996. Construction as reduction. Lund University, Dept. of Linguistics Working Papers. 1996. Vol. 45, p. 79–92. pdf 
⇒ Reduction of Possibilities