international sea and swell scale vs Douglas scale

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

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

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

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

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

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