sepsis vs septicaemia

sepsis and septicaemia both are nouns.

Word	Noun	Adjective	Verb	Adverb
sepsis	Yes	No	No	No
septicaemia	Yes	No	No	No

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

sepsis: the presence of pus-forming bacteria or their toxins in the blood or tissues
septicaemia: invasion of the bloodstream by virulent microorganisms from a focus of infection

Other hyponyms of sepsis include blood poisoning, septicemia, sapraemia, sapremia.

sepsis (noun)	septicaemia (noun)
the presence of pus-forming bacteria or their toxins in the blood or tissues	invasion of the bloodstream by virulent microorganisms from a focus of infection