tea leaf vs oolong

tea leaf and oolong both are nouns.

Word	Noun	Adjective	Verb	Adverb
tea leaf	Yes	No	No	No
oolong	Yes	No	No	No

As nouns, oolong is a hyponym of tea leaf; that is, oolong is a word with a more specific, narrower meaning than tea leaf:

tea leaf: dried leaves of the tea shrub; used to make tea
oolong: Chinese tea leaves that have been partially fermented before being dried

Other hyponyms of tea leaf include tea bag, black tea, green tea.

tea leaf (noun)	oolong (noun)
dried leaves of the tea shrub; used to make tea	Chinese tea leaves that have been partially fermented before being dried