leaf vs plant organ

leaf and plant organ both are nouns.

Word	Noun	Adjective	Verb	Adverb
leaf	Yes	No	Yes	No
plant organ	Yes	No	No	No

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

leaf (noun)	plant organ (noun)
hinged or detachable flat section (as of a table or door)	a functional and structural unit of a plant or fungus
a sheet of any written or printed material (especially in a manuscript or book)
the main organ of photosynthesis and transpiration in higher plants

leaf (verb)	plant organ (verb)
produce leaves, of plants
turn over pages
look through a book or other written material