romaine lettuce vs cos lettuce

romaine lettuce and cos lettuce both are nouns.

Word	Noun	Adjective	Verb	Adverb
romaine lettuce	Yes	No	No	No
cos lettuce	Yes	No	No	No

As nouns, romaine lettuce and cos lettuce are synonyms defined as:

romaine lettuce and cos lettuce: lettuce with long dark-green leaves in a loosely packed elongated head

Other synonyms of romaine lettuce include cos, romaine.

As nouns, romaine lettuce and cos lettuce are synonyms defined as:

romaine lettuce and cos lettuce: lettuce with long dark-green spoon-shaped leaves

Other synonyms of romaine lettuce include Lactuca sativa longifolia.

romaine lettuce (noun)	cos lettuce (noun)
lettuce with long dark-green leaves in a loosely packed elongated head	lettuce with long dark-green leaves in a loosely packed elongated head
lettuce with long dark-green spoon-shaped leaves	lettuce with long dark-green spoon-shaped leaves