leaf vs piece of paper

leaf and piece of paper both are nouns.

Word	Noun	Adjective	Verb	Adverb
leaf	Yes	No	Yes	No
piece of paper	Yes	No	No	No

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

leaf: a sheet of any written or printed material (especially in a manuscript or book)
piece of paper: paper used for writing or printing

Other hypernyms of leaf include sheet, sheet of paper.

leaf (noun)	piece of paper (noun)
hinged or detachable flat section (as of a table or door)	paper used for writing or printing
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)	piece of paper (verb)
produce leaves, of plants
turn over pages
look through a book or other written material