Rickettsiaceae vs rickettsia

Rickettsiaceae and rickettsia both are nouns.

Word	Noun	Adjective	Verb	Adverb
Rickettsiaceae	Yes	No	No	No
rickettsia	Yes	No	No	No

Rickettsiaceae (noun)	rickettsia (noun)
microorganism resembling bacteria inhabiting arthropod tissues but capable of causing disease in vertebrates	any of a group of very small rod-shaped bacteria that live in biting arthropods (as ticks and mites) and cause disease in vertebrate hosts; they cause typhus and other febrile diseases in human beings