doorlock vs night latch

doorlock and night latch both are nouns.

Word	Noun	Adjective	Verb	Adverb
doorlock	Yes	No	No	No
night latch	Yes	No	No	No

As nouns, night latch is a hyponym of doorlock; that is, night latch is a word with a more specific, narrower meaning than doorlock:

doorlock: a lock on an exterior door
night latch: doorlock operated by a knob on the inside and a key on the outside

doorlock (noun)	night latch (noun)
a lock on an exterior door	doorlock operated by a knob on the inside and a key on the outside