leaflet vs foliage

leaflet and foliage both are nouns.

Word	Noun	Adjective	Verb	Adverb
leaflet	Yes	No	No	No
foliage	Yes	No	No	No

As nouns, foliage is a hypernym of leaflet; that is, foliage is a word with a broader meaning than leaflet:

leaflet: part of a compound leaf
foliage: the main organ of photosynthesis and transpiration in higher plants

Other hypernyms of leaflet include leaf, leafage.

leaflet (noun)	foliage (noun)
a thin triangular flap of a heart valve	(architecture) leaf-like architectural ornament
a small book usually having a paper cover	the main organ of photosynthesis and transpiration in higher plants
part of a compound leaf