litre vs metric capacity unit

litre and metric capacity unit both are nouns.

Word	Noun	Adjective	Verb	Adverb
litre	Yes	No	No	No
metric capacity unit	Yes	No	No	No

As nouns, metric capacity unit is a hypernym of litre; that is, metric capacity unit is a word with a broader meaning than litre:

litre: a metric unit of capacity, formerly defined as the volume of one kilogram of pure water under standard conditions; now equal to 1,000 cubic centimeters (or approximately 1.75 pints)
metric capacity unit: a capacity unit defined in metric terms

litre (noun)	metric capacity unit (noun)
a metric unit of capacity, formerly defined as the volume of one kilogram of pure water under standard conditions; now equal to 1,000 cubic centimeters (or approximately 1.75 pints)	a capacity unit defined in metric terms