leaf lettuce vs lettuce

leaf lettuce and lettuce both are nouns.

Word	Noun	Adjective	Verb	Adverb
leaf lettuce	Yes	No	No	No
lettuce	Yes	No	No	No

As nouns, lettuce is a hypernym of leaf lettuce; that is, lettuce is a word with a broader meaning than leaf lettuce:

leaf lettuce: lettuce with loosely curled leaves that do not form a compact head
lettuce: leaves of any of various plants of Lactuca sativa

As nouns, lettuce is a hypernym of leaf lettuce; that is, lettuce is a word with a broader meaning than leaf lettuce:

leaf lettuce: distinguished by leaves having curled or incised leaves forming a loose rosette that does not develop into a compact head
lettuce: any of various plants of the genus Lactuca

leaf lettuce (noun)	lettuce (noun)
lettuce with loosely curled leaves that do not form a compact head	leaves of any of various plants of Lactuca sativa
distinguished by leaves having curled or incised leaves forming a loose rosette that does not develop into a compact head	any of various plants of the genus Lactuca
	informal terms for money