hooter vs alarm system

hooter and alarm system both are nouns.

Word	Noun	Adjective	Verb	Adverb
hooter	Yes	No	No	No
alarm system	Yes	No	No	No

As nouns, alarm system is a hypernym of hooter; that is, alarm system is a word with a broader meaning than hooter:

hooter: a device on an automobile for making a warning noise
alarm system: a device that signals the occurrence of some undesirable event

Other hypernyms of hooter include alarm, warning device.

hooter (noun)	alarm system (noun)
nocturnal bird of prey with hawk-like beak and claws and large head with front-facing eyes	a device that signals the occurrence of some undesirable event
a device on an automobile for making a warning noise
informal terms for the nose