internment vs custody

internment and custody both are nouns.

Word	Noun	Adjective	Verb	Adverb
internment	Yes	No	No	No
custody	Yes	No	No	No

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

Other hyponyms of internment include lockdown, false imprisonment.

internment (noun)	custody (noun)
the act of confining someone in a prison (or as if in a prison)	holding by the police
placing private property in the custody of an officer of the law	(with `in') guardianship over; in divorce cases it is the right to house and care for and discipline a child
confinement during wartime	a state of being confined (usually for a short time)