Collocations for code - noun

secret
Morse

break, crack, decipher
The code was difficult to crack.

use, write in
invent, make up

name, phrase, word
breaker

in code
All the messages were in code.

area (esp. AmE), dialling (BrE)
What's the area code for Boston?

post (usually postcode), postal (BrE), zip (AmE)
bar, charge (BrE)
security
three-letter, four-digit, etc.
DNA, genetic
error (= on a computer)

generate

number
generator

binary (= a system of computer programming instructions), executable, HTML, source
malicious

execute
write
modify, rewrite

strict
unwritten
There is an unwritten code that says ‘Do not date your best friend's ex’.

ethical, moral, professional
civil, criminal, disciplinary, penal, tax
planned changes in the US tax code

Highway
the Highway Code (= the official rules for users of public roads in Britain)

dress

have
adopt, draw up, establish, formulate, lay down (esp. BrE)
The company has drawn up a new disciplinary code.

enforce
revise, simplify
comply with, follow
break, infringe (esp. BrE), violate
The principal said I had violated the school's dress code.

a code of behaviour/behavior, a code of conduct
a code of ethics
a code of honour/honor
a code of practice
The profession has a strict code of practice.