code of conduct vs convention

code of conduct and convention both are nouns.

Word	Noun	Adjective	Verb	Adverb
code of conduct	Yes	No	No	No
convention	Yes	No	No	No

As nouns, convention is a hypernym of code of conduct; that is, convention is a word with a broader meaning than code of conduct:

code of conduct: a set of conventional principles and expectations that are considered binding on any person who is a member of a particular group
convention: something regarded as a normative example

Other hypernyms of code of conduct include formula, normal, pattern, rule.

code of conduct (noun)	convention (noun)
a set of conventional principles and expectations that are considered binding on any person who is a member of a particular group	the act of convening
	orthodoxy as a consequence of being conventional
	something regarded as a normative example
	(diplomacy) an international agreement
	a large formal assembly