iceberg vs Lactuca sativa capitata

iceberg and Lactuca sativa capitata both are nouns.

Word	Noun	Adjective	Verb	Adverb
iceberg	Yes	No	No	No
Lactuca sativa capitata	Yes	No	No	No

iceberg (noun)	Lactuca sativa capitata (noun)
lettuce with crisp tightly packed light-green leaves in a firm head	distinguished by leaves arranged in a dense rosette that develop into a compact ball
a large mass of ice floating at sea; usually broken off of a polar glacier