betel leaf vs foliage

betel leaf and foliage both are nouns.

Word	Noun	Adjective	Verb	Adverb
betel leaf	Yes	No	No	No
foliage	Yes	No	No	No

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

betel leaf: a leaf of a vine from the betel pepper
foliage: the main organ of photosynthesis and transpiration in higher plants

Other hypernyms of betel leaf include leaf, leafage.

betel leaf (noun)	foliage (noun)
a leaf of a vine from the betel pepper	(architecture) leaf-like architectural ornament
	the main organ of photosynthesis and transpiration in higher plants