espresso vs latte

espresso and latte both are nouns.

Word	Noun	Adjective	Verb	Adverb
espresso	Yes	No	No	No
latte	Yes	No	No	No

As nouns, latte is a hyponym of espresso; that is, latte is a word with a more specific, narrower meaning than espresso:

espresso: strong black coffee brewed by forcing hot water under pressure through finely ground coffee beans
latte: strong espresso coffee with a topping of frothed steamed milk

Other hyponyms of espresso include caffe latte.

espresso (noun)	latte (noun)
strong black coffee brewed by forcing hot water under pressure through finely ground coffee beans	strong espresso coffee with a topping of frothed steamed milk