code flag vs nautical signal flag

code flag and nautical signal flag both are nouns.

Word	Noun	Adjective	Verb	Adverb
code flag	Yes	No	No	No
nautical signal flag	Yes	No	No	No

As nouns, code flag and nautical signal flag are synonyms defined as:

code flag and nautical signal flag: one of an international code of flag signals used between ships

code flag (noun)	nautical signal flag (noun)
one of an international code of flag signals used between ships	one of an international code of flag signals used between ships