iceberg lettuce vs crisphead lettuce

iceberg lettuce and crisphead lettuce both are nouns.

Word	Noun	Adjective	Verb	Adverb
iceberg lettuce	Yes	No	No	No
crisphead lettuce	Yes	No	No	No

As nouns, iceberg lettuce and crisphead lettuce are synonyms defined as:

iceberg lettuce and crisphead lettuce: lettuce with crisp tightly packed light-green leaves in a firm head

Other synonyms of iceberg lettuce include iceberg.

iceberg lettuce (noun)	crisphead lettuce (noun)
lettuce with crisp tightly packed light-green leaves in a firm head	lettuce with crisp tightly packed light-green leaves in a firm head