international sea and swell scale vs Douglas sea scale

international sea and swell scale and Douglas sea scale both are nouns.

Word	Noun	Adjective	Verb	Adverb
international sea and swell scale	Yes	No	No	No
Douglas sea scale	Yes	No	No	No

As nouns, international sea and swell scale and Douglas sea scale are synonyms defined as:

international sea and swell scale and Douglas sea scale: scale used for measuring the height of waves

Other synonyms of international sea and swell scale include Douglas scale.

international sea and swell scale (noun)	Douglas sea scale (noun)
scale used for measuring the height of waves	scale used for measuring the height of waves